SEASONAL BEHAVIOURS OF COASTAL CUTTHROAT TROUT (ONCORHYNCHUS CLARKII
CLARKII) IN THE KITIMAT RIVER WATERSHED: OBSERVATIONS AND INFLUENCES

by

Eric Adam Vogt

B.Sc., The University of British Columbia, 2010

THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE
DEGREE OF MASTER OF SCIENCE
IN
NATURAL RESOURCE AND ENVIRONMENTAL STUDIES
(BIOLOGY)

UNIVERSITY OF NORTHERN BRITISH COLUMBIA
April 2017

© Eric Adam Vogt, 2017

ABSTRACT
Coastal cutthroat trout (O. clarkii clarkii, CCT) are arguably the most poorly
understood species of salmonid and little is known of their seasonal patterns of movement,
particularly in British Columbia. My study was conducted to assess the overwintering and
spawning behaviours of migratory CCT in the Kitimat River watershed and to evaluate how
behaviours were influenced by a suite of biotic and abiotic metrics. Radio transmitters were
surgically implanted into mature CCT in the late summer and fall of 2012 (Year 1; n = 41)
and 2013 (Year 2; n = 68). In the late fall, CCT aggregated within deep, slow moving pools.
During the winter, CCT either remained stationary within a single overwintering habitat, or
were mobile, moving among 2 to 5 habitats. Spawning occurred in first to third order
tributaries throughout the watershed, from April 14 to May 15. Spawning mortality was
high, and 57% of radio tagged CCT did not survive spawning. I used an information-theoretic
model to assess the influence of mean daily mainstem water temperature and discharge,
photoperiod, thermal experience (accumulated thermal units [ATU]), distance travelled to
spawn, migration type (mobile or stationary), fork length and sex on the timing that CCT
moved out of overwintering habitats and into spawning tributaries. The analysis
demonstrated the inherent seasonality of when spawning migrations are initiated and
suggested that photoperiod combined with fork length and distance to spawn was best able
to predict when CCT moved out of overwintering habitats. The spawning analysis
demonstrated that when CCT arrive in spawning tributaries was most strongly influenced by
combinations of thermal experience, photoperiod and migration type. My study has
provided a comprehensive review of the overwintering and spawning behaviours of
migratory CCT at a spatial and temporal scale that has not been completed previously.
Behaviours associated with life history events, however, exhibited tremendous variability
which has reinforced the need for local, watershed specific research when considering
management strategies for the species.

ii

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LIST OF TABLES
Table 1.1. Regional variation in timing of returns to freshwater (FW Return),
spawning and downstream migrations of anadromous coastal cutthroat trout
in Alaska, British Columbia (BC), Washington (WA) and Oregon (OR). Light
and dark green squares indicate range and peak timing of behaviours,
respectively. ..................................................................................................... 9
Table 1.2. Summary of location and operation period of stationary receiver stations
in the Kitimat watershed. ............................................................................... 20
Table 1.3. Summary of tests applied to stationary receiver data to remove potential
erroneous detections. .................................................................................... 21
Table 1.4. Mainstem river position (rkm) of radio tagged CCT at capture in year 1 and
year 2. ............................................................................................................. 29
Table 1.5. Percent of CCT spawning in major and minor tributaries within the lower,
middle and upper reaches of the Kitimat watershed. .................................... 55
Table 1.6. Summary of the relative mortality of CCT spawning within the main
channel, and secondary and tertiary streams of major and minor tributaries
to the Kitimat River. ....................................................................................... 57
Table 2.1. Summary of grand mean and minimum water temperatures recorded at
mainstem temperature logging sites in year 1 and year 2 from November 1 to
May 31. ........................................................................................................... 82
Table 2.2. Summary of ANOVA and Tukey multiple comparison tests comparing
mean mainstem discharge from October to May in year 1 and year 2 to mean
daily historic flows from 1965 to 2012. .......................................................... 84
Table 2.3. Correlations between metrics included in the analysis of departure from
overwintering habitats. .................................................................................. 85
Table 2.4. Correlations between metrics included in the analysis of arrival in to
spawning tributaries. ...................................................................................... 85
Table 2.5. Summary of abiotic measures calculated for temporal intervals included in
the overwintering analysis. Tests for differences between years are
presented in the final column. ....................................................................... 87
Table 2.6. Set of logistic regression candidate models used to estimate likelihood of
movement out of overwintering habitats for CCT radio tagged in the Kitimat
River in year 1 and year 2. Standard errors in each model were clustered by
individual CCT. Fixed effect variables include: Photoperiod, a continuous
measure of mean civil day length (hr); Temperature and Discharge, measures
of mean mainstem water temperature and discharge, respectively; ATU,
running sum of mean daily mainstem water temperature; Distance, measure
of the total absolute distance (km) each CCT travelled to spawn from final
overwintering habitats; Mig.Type, a dichotomous measure identifying mobile
(1) and stationary CCT (0); Sex, a dichotomous variable identifying male (0)
and female (1) CCT, and; FL, a measure of the fork length (mm) of individual
CCT.................................................................................................................. 89
v

Table 2.7. Diagnostic summary of overwintering candidate models with AICc values
less than 2. Fixed effect variables include: Photoperiod, a continuous
measure of mean civil day length (hr); Discharge, a measure of mean
mainstem discharge; Distance, measure of the total absolute distance (km)
each CCT travelled to spawn from final overwintering habitats, and; FL, a
measure of the fork length (mm) of individual CCT. ...................................... 90
Table 2.8. Summary of measures of photoperiod (hr), temperature (°C), thermal
experience (ATU, °C) and discharge (m/s3) calculated for temporal intervals
included in the spawning analysis. ................................................................. 92
Table 2.9. Set of logistic regression candidate models used to estimate likelihood of
movement into spawning tributaries for CCT radio tagged in the Kitimat River
in year 1 and year 2. Standard errors in each model were clustered by
individual CCT. Fixed effect variables include: Photoperiod, a continuous
measure of mean civil day length (hr); Temperature and Discharge, measures
of mean mainstem water temperature and discharge, respectively; Distance,
measure of the total absolute distance (km) each CCT travelled to spawn
from final overwintering habitats; Mig.Type, a dichotomous measure
identifying mobile (1) and stationary CCT (0); Sex, a dichotomous variable
identifying male (0) and female (1) CCT, and; FL, a measure of the fork length
(mm) of individual CCT. .................................................................................. 93
Table 2.10. Diagnostic summary of spawning candidate models with AICc values less
than 2. Standard errors in each model were clustered by individual CCT. Fixed
effect variables include: Photoperiod, a continuous measure of mean civil
day length (hr); ATU, a measure of cumulative mean daily mainstem water
temperature; Discharge, measure of mean mainstem discharge, and;
Mig.Type, a dichotomous measure identifying mobile (1) and stationary CCT
(0). .................................................................................................................. 94
Table A2.1. Observations identified in scientific literature supporting the inclusion of
abiotic metrics in the overwintering candidate model set. .......................... 171
Table A2.2. Observations identified in scientific literature supporting the inclusion of
abiotic metrics in the spawning candidate model set. ................................. 172
Table A2.3. Mean water temperature recorded in tributaries of the Kitimat river
throughout the overwinter period (October 1 to March 14), spawning period
(March 15 to May 31) and combined periods (October 1 to May 31) of each
year. .............................................................................................................. 174
Table A2.4. Summary of date that radio tagged CCT were first observed in spawning
tributaries and the temperature of spawning tributaries upon arrival. ....... 175

vi

LIST OF FIGURES
Figure 1.1. Position of stationary antenna arrays within the Kitimat watershed. ...... 16
Figure 1.2. Histogram comparing the location that radio tagged CCT were sampled
throughout the Kitimat watershed................................................................. 28
Figure 1.3. Fork length frequency histogram of all CCT captured in 2012 and 2013. 30
Figure 1.4. Fork length (A), weight (B), age (C) and condition factor (D) of male and
female CCT radio tagged with large transmitters in year 1 and year 2. ......... 33
Figure 1.5. Fork length (A), weight (B), age (C) and condition factor of mobile and
stationary CCT tagged with large transmitters in year 1 and 2. ..................... 36
Figure 1.6. Position of winter aggregation areas (red dots) used by radio tagged CCT
in the Kitimat watershed. ............................................................................... 38
Figure 1.7. Mean river and tributary position of initial overwintering habitats used by
radio tagged CCT in year 1 and 2. Note that northern and southern tributaries
are identified by positive and negative values of tributary position,
respectively. ................................................................................................... 39
Figure 1.8. Mean river and tributary position of final overwintering habitats used by
radio tagged CCT in year 1 and 2. Note that northern and southern tributaries
are identified by positive and negative values of tributary position,
respectively. ................................................................................................... 39
Figure 1.9. Date that male and female CCT were captured within (A), and first
relocated within (B), initial overwintering habitats in in year 1 and 2. Note
CCT that were captured in overwintering habitats are not included in Figure
1.9A. ............................................................................................................... 41
Figure 1.10. Date that mobile and stationary CCT were captured within (A), and first
relocated within (B), initial overwintering habitats in in year 1 and 2. Note
CCT that were captured in overwintering habitats are not included in Figure
1.10A. ............................................................................................................. 41
Figure 1.11. Comparison of the relative proportion of radio tagged CCT (dotted line)
that were observed (solid line) and captured (dashed line) in overwintering
habitats in year 1 and 2. The dates when aerial relocation flights were
conducted are indentified by circles. The median date when radio tagged CCT
were observed within overwintering habitats in each year is identified by an
“X”. Note that the relative proportion of CCT observed within overwintering
habitats (dashed line) includes CCT that travelled to overwintering habitats,
as well as CCT that were captured within overwintering habitats. ................ 42
Figure 1.12. Mean and SE absolute distance male and female (A), and mobile and
stationary (B) CCT travelled through the mainstem from their location of
capture to initial overwintering habitats in year 1 and 2. .............................. 44
Figure 1.13. Mean and SE absolute distance male and female (A), and mobile and
stationary (B) CCT travelled through the mainstem and tributaries from their
location of capture to initial overwintering habitats in year 1 and 2. ............ 44

vii

Figure 1.14. Mean river position of overwintering aggregation areas in the Kitimat
watershed in year 1 and 2. The size of each point corresponds to the number
of fish observed within each overwintering area. Initial overwinter (OW)
areas represent the first overwintering habitat that mobile and stationary
radio tagged CCT were observed within. The three lower panels represent
the position of the second, third and fourth overwintering habitats used by
mobile CCT, and thus demonstrate how the distribution of mobile CCT
changed over time. Note that northern and southern tributaries are
identified by positive and negative values of tributary position, respectively.
........................................................................................................................ 46
Figure 1.15. Correlation between the date that radio tagged CCT departed final
overwintering habitats and the total distance travelled (rkm + tkm) to spawn.
........................................................................................................................ 48
Figure 1.16. Median date non-staging male and female (A) and mobile and
stationary (B) CCT departed overwintering habitats in year 1 and year 2. .... 48
Figure 1.17. Median date staging male and female (A) and mobile and stationary (B)
CCT departed overwintering habitats in year 1 and year 2. ........................... 49
Figure 1.18. Median date that staging (A) and non-staging (B) male and female CCT
arrived in spawning tributaries in year 1 and year 2 ...................................... 53
Figure 1.19. Median date that staging (A) and non-staging (B) mobile and stationary
CCT arrived in spawning tributaries in year 1 and year 2. .............................. 53
Figure 1.20. Location of putative spawning habitats (red dots) used by radio tagged
CCT in the Kitimat watershed. ........................................................................ 55
Figure 2.1. Map of the Kitimat Watershed. Red circles indicate the position of
temperature loggers; green squares indicate the position of Environment
Canada hydrometric gauges. .......................................................................... 77
Figure 2.2. Trends in daily measures of day length recorded in Kitimat BC, from
October 1 to June 1. ....................................................................................... 82
Figure 2.3. Profile of mean and minimum daily mainstem water temperature from
October 1 to May 31 of year 1 and year 2. Temperatures recorded at 11.2
rkm on the Kitimat River. ............................................................................... 83
Figure 2.4. Profile of mean and minimum daily discharge in the Kitimat River in year
1 and year 2. ................................................................................................... 83
Figure 2.5. Environmental conditions and count of the number of fish moving per
period in year 1 and 2. Each period represents 4 days, starting on February
15. Line plots compare mean water temperature (Temp., °C), accumulated
thermal units (ATU, sum of mean daily temperature), discharge (Flow, m3s-1),
and day length (Photo, hr) per period in year 1 and year 2. Histograms
summarize the total number of CCT observed moving out of overwintering
habitats (OW) and into spawning tributaries (Spawn) during each period. ... 88
Figure A1.1. Fork length (A), weight (B), age (C) and condition factor (D) of all CCT
sampled during angling. ............................................................................... 141
Figure A1.2. Condition of CCT ID#3 upon recapture on November 16, 2012. Note the
yellow discoloration at the exit point of the antenna as well as on abdomen
viii

where transmitter appears to be resting. Fish was not relocated again 1
month after this photo was taken. ............................................................... 169
Figure A1.3. Condition of CCT ID#51 upon recapture on March 15, 2013. The
transmitter in this CCT was recovered on April 19, 2013 and the fish is
assumed to have died................................................................................... 169
Figure A1.4. Condition of CCT ID#134 upon recapture on July 14, 2014. The incision
appears to have healed cleanly and sutures have dissolved. ....................... 170
Figure A1.5. Condition of CCT ID#148 upon recapture on April 24, 2014. Note that
scar, circled in red has healed cleanly. Abscess is possibly due to wear against
the transmitter. ............................................................................................ 170

ix

ACKNOWLEDGEMENTS
First and foremost, I would like to acknowledge the support of my supervisory
committee. I am thankful for the contributions of my supervisor, Dr. Allan Costello. This
project would not have been possible without him. I am honoured to have had the
opportunity to work closely with my co-supervisor, Dr. Mark Shrimpton. His patience,
support and experience were inspiring. The insight and fresh perspectives provided by Dr.
Daniel Erasmus were invaluable. Although not a member of my committee, I would like to
thank Dr. Chris Johnson for his analytical support. I am grateful to have had funding from
the Habitat and Conservation Trust Fund.
Skeena Region Fish & Wildlife biologists Jeff Lough and Joe De Gisi were critical to
the success of this project. Jeff, I am incredibly grateful to have worked with you and for all
that you have taught me. I am also very appreciative of the support provided by Markus
Feldhoff and Vince Sealy as well as the rest of the staff at the Kitimat River Fish Hatchery.
Ben Millard Martin and Greg Winter, thank you for your support and patience in the field.
Dean Miller, I am thankful for your mastery of telemetry and hot tubs.
I would like to thank the locals of Kitimat and Terrace who volunteered to help with
sampling. There are too many names to list, but there are some that cannot be ignored. A
very special thank you goes to Brian and Jennifer Kean for making me feel at home in a new
community. Brian, I hope that one day I will have as many fishing stories as you. Mitch
Drews was also a tremendous help and was a valuable source of knowledge, humour, flies
and taggable cutthroat. I would also like to thank Jason Bunn, Trent Vines and Steven Reid
for sharing many of their trout with me.
I was very fortunate to have received support from family and friends and want to
express a special thank you to Peter Clarke, Thomas Towers, Sophia Harrison, Dave Eng,
Kristi Serwa, Quinn, Ros, Fisher and Tully Barabash; Eric, Carla, Maelle and Daeyin Lennert;
Ian Riemenschneider, Kamryn McFarlane, Mike Dewer, Kim Tuor, Wyatt Klopp, Amy
Blanding, Marley Bassett, Brett Leversage, Wes McKay, Cedar Welsh, David Vogt and Tracy
Proke.
I am indebted to my family for their unconditional love, support and encouragement
during this chapter of my life and for instilling in me a curious mind and a passion for nature
and the outdoors. Shannon, thank you for your patience during this journey. I am thrilled to
be starting my next chapter with you.
Finally, thank you (and my apologies) to all the beautiful cutthroat that I sampled.

x

PROLOGUE
The movement of animals across heterogeneous landscapes is poorly understood,
but movement patterns are a fundamental component of understanding the biology of a
species. Movements are responsible not only for the contemporary distribution and
assemblage of species that exist today (Hanski 1999, Brunsfeld et al. 2001), but continue to
influence species evolution by promoting gene flow and colonization of new habitats
(Hanski 1999, Hanski and Gaggiotti 2004, Brenkman et al. 2008). It is ultimately the
individual’s ability to move through the environment, both into critical habitats and away
from degraded habitats and predators that permits its continued persistence (Roff 1974,
Kareiva et al. 1990, Pickett and Cadenasso 1995). Thus, a thorough understanding of the
potential forces influencing species movement is necessary to make accurate ecological
predictions on the effects of habitat fragmentation, climate change, or other anthropogenic
impacts on species (Saunders et al. 1991, Walther et al. 2002, Morales et al. 2010).
The challenges of understanding species movements and range of migratory
behaviours, however, can be substantial. One of the greatest challenges in understanding
behaviour of a species is simply observing them, as individuals often reside within
environments that are inhospitable to humans or undergo movements that occur over vast
spatial and temporal scales (Belisle 1986). Even when movements are readily detected,
variability among individuals and populations may limit the ability to extrapolate patterns
that are representative of larger populations (Waples and Gaggiotti 2006, Cagnacci et al.
2010).

1

These difficulties are often encountered in members of the Family Salmonidae.
Throughout their life cycle, salmonids are dependent on a diverse array of habitats, from
small rearing streams to productive marine foraging areas. Often, these habitats are
separated by considerable distances, requiring salmonids to make significant movements
and migrations to forage and reproduce. While long distance migrations can be risky and
physiologically demanding, the ontogenic partitioning of resources permits the
development of far greater population densities than would otherwise be possible within a
single homogenous habitat (Quinn 2011).
There are clear ecological and evolutionary advantages that favour dispersal and
migration to high quality foraging and reproductive habitats. For example, gene flow among
populations can contribute to genotypic variation and reproductive success is often
positively correlated with body size (Beacham and Murray 1993, Bohonak 1999, Wenburg
and Bentzen 2001). Thus, migration and movement between critical habitats are central to
the viability of salmon populations, necessitating the maintenance of not only life history
stage-specific habitats, but also migration corridors between them. While effective
conservation and management requires a thorough understanding of salmonid migration
patterns and habitat requirements, the large spatial and temporal scales at which these
behaviours typically occur make this task inherently challenging.
A particularly interesting salmonid is the coastal cutthroat trout (Oncorhynchus
clarkii clarkii). The most widely distributed of the 14 cutthroat trout subspecies, coastal
cutthroat trout (CCT) range from the Eel River in California to Gore Point in Alaska, roughly
coinciding with the Pacific temperate rainforest (Behnke 1992). Populations are
2

predominantly found in small to medium sized watersheds draining directly into the Pacific
Ocean, however, they have also been documented in the lower tributaries of larger systems
such as the Fraser, Skeena and Stikine Rivers in British Columbia as well as the Columbia
River in Oregon and Washington (Johnson et al. 1999, Connolly et al. 2005, Costello and
Rubidge 2005). CCT are relatively small in comparison to anadromous salmonids, a
characteristic that has permitted the subspecies to occupy and reside within freshwater
habitats that are generally inaccessible to larger salmonids (Trotter 2008). Unfortunately,
the small, low gradient headwater streams the subspecies is dependent upon are areas that
are often coveted for human development and are often overlooked by landscape
managers (Rosenfeld et al. 2002, Costello and Rubidge 2005, Slaney and Roberts 2005).
Consequently, forest harvesting, agricultural practices and urban development have
contributed to dramatic declines in the subspecies abundance throughout the last century.
While declines have been the greatest throughout the highly developed southern portion of
the subspecies range, it is expected that continued resource extraction and development in
northern regions may produce similar detrimental effects (Johnson et al. 1999, Wildlife
2004, Connolly et al. 2005, Costello and Rubidge 2005, Slaney and Roberts 2005, Stein et al.
2012a).
Unlike other Pacific salmonids, CCT populations tend to be small; typically in the
order of 100’s to 1000’s of individuals, of which mature breeding individuals may be limited
to 10’s to 100’s (Sumner 1952, Slaney and Roberts 2005, Costello 2006). Within populations,
life history behaviours are incredibly diverse and it is not uncommon for multiple life history
strategies to exist in sympatry within the same watershed (Sumner 1972, Trotter 1989). It is
3

also not uncommon for individuals to switch between strategies throughout their life. For
example, an individual may move into marine environments one year and then return to
freshwater habitats for two years before returning to marine environments again. While,
CCT do migrate between critical spawning, foraging and overwintering habitats, the species
is perhaps better known for its wandering, opportunistic movements that are frequently
associated with seasonally abundant food sources (i.e. eggs during spawning of Pacific
salmon; Bilby et al. 1996). Although the general timing and duration of movements within
populations appear to be relatively consistent, there is a high degree of variability among
populations and even among individuals within populations. The fact that multiple life
history strategies, each showing unique movement behaviours, are often present within the
same system adds further complexity to the subspecies movements. Not surprisingly then,
the movement behaviours and migration patterns of CCT are arguably among the most
complex, and least understood, of any salmonid (Trotter 2008).
There is however, a growing impetus to unravel the ecology of CCT, as this salmonid
has suffered significant population declines throughout its range in recent years due to
habitat alteration, over harvesting and species introductions (Johnson et al. 1999, Connolly
et al. 2005, Costello 2008). While many, if not most, of British Columbia’s medium sized
coastal watersheds have been heavily impacted by forest harvesting throughout the last
century, few have been further subjected to the extent of industrialization and urban
development that has occurred throughout the Kitimat River watershed (Macdonald and
Shepherd 1983, Karanka 1993, Simpson et al. 1998). Despite these impacts, the Kitimat
River remains one of the most popular recreational angling destinations on the British
4

Columbia coast, primarily due to ease of access, proximity to population centers and the
large numbers of returning hatchery raised Pacific salmon and steelhead trout (DFO 2009).
Future pipeline and refinery developments in this region can be expected to not only
further degrade habitat, but also indirectly increase angling pressure as these new
industries attract workers. There is a need, therefore, to develop and institute conservation
and management strategies aimed at salmonids in this watershed. This is of particular
importance for species such as the CCT, which are particularly vulnerable to anthropogenic
disturbances (Slaney and Roberts 2005). Doing so, however, requires a detailed knowledge
of this subspecies life history related movements and migration behaviours between critical
habitats.
To address these issues and contribute to the development of local conservation
strategies for migratory CCT, this study employed radio telemetry to investigate the life
history strategies and movement patterns of CCT within the Kitimat River. The first chapter
of this study describes the overwintering and spawning behaviours of CCT in the Kitimat
watershed. In Chapter 2, I examine the extent to which a suite of biotic and abiotic factors
influence the timing of migrations from overwintering to spawning habitats. This research
provides a comprehensive overview of the seasonal behaviours and habitat use of CCT in
the northern portion of their geographic distribution and contributes to the development of
science-based conservation and management initiatives in the region.

5

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rear in small tributary and headwater streams but make short (3-8 month) migrations to
marine environments to forage (Trotter 1989, Behnke 1992, McDowall 1997, 2001).
Typically, multiple life history strategies will exist sympatrically within a watershed. Our
current understanding suggests that the development of multiple life history strategies
allows CCT to exploit the full spectrum of available habitats within coastal watersheds while
also acting as buffer to environmental stochasticity (Northcote 1997a, Trotter 2008, Quinn
2011).
The development of multiple life history strategies and stream to stream wandering
behaviour, however, may be opportunistic and allow CCT to exploit seasonally abundant
food resources (Jones 1975, Johnson et al. 1999). Although aquatic invertebrates compose
the majority of the subspecies diet in both marine and freshwater environments, individuals
become increasingly piscivorous as they increase in size and will move extensively to
capitalize upon seasonally abundant food sources (Sumner 1972, Pauley et al. 1989, Jones
et al. 2008). For example, sea-run and fluvial CCT will move into lower river reaches to eat
migrating salmon smolts in the spring and will follow spawning salmon upstream to forage
on their eggs and carcasses in the fall (Giger 1972, Trotter 1989, Saiget et al. 2007). This
opportunistic feeding strategy has likely influenced the subspecies contemporary
distribution and resiliency (Trotter 2008).
Although CCT do make life history specific migrations between habitats, these
movements may, in fact, be highly flexible, given the diversity of habitats the species
occupies and the temporal variation of individual’s movements both within and among
populations (e.g. Saiget et al. 2007). The factors influencing life history strategies of CCT are
7

not fully understood, however, it appears that many of the same factors that structure the
life histories of salmonids, namely natal stream conditions and stability, population density
and species composition, migration distances between required habitats, and the relative
sex selective advantages of migration also affect CCT (Jonsson and Jonsson 1993).
Coastal cutthroat trout do not typically remain in marine environments for more
than 6-8 months (Mercer and Johnston 1979, Mercer 1980; but see Krentz 2007) and
primarily return to fresh water for the winter where they overwinter in large deep pools
that provide refuge from unfavourable stream conditions (i.e. extreme temperatures, high
and low stream flows and ice flows) and are in proximity to food sources (i.e. emerging fry;
Giger 1972, Johnston 1981, Behnke 1992, Trotter et al. 1993). Geographical differences in
climate, condition and availability of suitable habitat appear to influence the use of
overwintering habitats. In the southern portion of the subspecies range, where climates are
relatively mild and winter precipitation is predominantly rain, there is less variability in
winter stream flows and individuals primarily overwinter in large pools within the mainstem
of their natal streams (Michael 1983, Hudson et al. 2008). Further north, sea-run CCT often
overwinter in coastal lakes and beaver ponds, which may or may not be within natal
watersheds (Jones and Harding 1998, Jones and Yanusz 1998, Saiget et al. 2007).
While some southerly populations may spawn as early as February, it appears that
spawning occurs in the spring throughout much of the species range, typically from early
April until June with peaks in early May (Table 1.1; Trotter 2008). Regardless of location or
life history form, CCT primarily spawn in the most upstream sections of first and second
order streams. Spawning in these upper stream reaches may act to increase spatial
8

reproductive isolation when the subspecies occurs in sympatry with steelhead trout (O.
mykiss; Ostberg et al. 2004, Buehrens et al. 2013). It has generally been perceived that
mature CCT move from overwintering habitats directly to spawning grounds (e.g. Saiget et
al. 2007), however this process may be more complex and some individuals may move out
of overwintering habitats towards staging or foraging areas prior to moving to spawning
grounds (pers. observation). Once on the spawning grounds, CCT typically remain within the
immediate vicinity of their redds for a period of days or even weeks (Costello 2006, Saiget et
al. 2007, Losee et al. 2016). Throughout the spawning period, pairs are unlikely to move
more than 100 m from the spawning habitat (Saiget et al. 2007). Individuals may reside
within spawning streams for as little as one to two days or as long as three to four weeks
(Costello 2006, Saiget et al. 2007).
Table 1.1. Regional variation in timing of returns to freshwater (FW Return), spawning and downstream
migrations of anadromous coastal cutthroat trout in Alaska, British Columbia (BC), Washington (WA) and
Oregon (OR). Light and dark green squares indicate range and peak timing of behaviours, respectively.

Region

Behaviour

AK

FW Return
Spawning
Outmigration

BC

FW Return
Spawning
Outmigration

WA

FW Return
Spawning
Outmigration

OR

FW Return
Spawning
Outmigration

1

2

3

4

5

Month
6
7

8

9

10

11

12

Regional References: Alaska: Jones & Harding 1998, Jones & Yanusz 1998, Saiget et al. 2007, Marston et al.
2011. British Columbia: Slaney & Roberts 2005. Washington: June 1981, Michael 1989, Garrett 1998, Moore et
al. 2010, Buehrens 2011. Oregon: Sumner 1972, Pearcy et al. 1990; Johnson et al. 1994; Stein et al. 2012.

9

Studying the movement and behaviours of any species in their natural environment
is inherently challenging, but when the species of interest cannot be directly observed and
movements occur over extended spatial and temporal scales these challenges are
compounded. Fortunately, many creative and effective methods have been, and continue
to be, developed to directly and indirectly track individuals in aquatic environments.
Telemetry, both radio and acoustic, are technologies that have greatly contributed to our
current understanding of the life history and movement behaviours of fish (Adams et al.
2012), including CCT. Recent studies employing telemetry in the lower Columbia River, for
example, have provided the most comprehensive review of anadromous CCT movement
patterns in the southern region of the species range (Hudson et al. 2008, Johnson 2008,
2009, Zydlewski et al. 2008, 2009). These studies have demonstrated that both mature and
juvenile emigrants use the lower Columbia River tributaries, mainstem, plume and estuary
extensively, that downstream migrations are strongly influenced by both diel and tidal
cycles, and that individuals regularly make 3 to 5 km crossings of the shipping channel.
Telemetry studies in Alaska have focused primarily on spawning behaviours and have
identified size and sex gradients among spawners (Jones and Yanusz 1998), have described
the variability in spawning behaviours of diadromous and fluvial CCT (Saiget et al. 2007),
and have documented spawning habitats and migration behaviours (Marston et al. 2011).
While similarities do exist in the behaviours of southern and northern CCT populations,
tracking studies reinforce the inherent variability in behaviours among and within
populations and suggest a high degree of adaptation to the local environment.

10

Despite the insight that these studies have provided into the behaviours of CCT,
there is still a strong argument to be made that CCT are among the most poorly understood
species of salmonid (Trotter 2008). Certainly, there has been far less systematic research
into the ecology and behaviours of this subspecies relative to other salmonids. All too often,
stream specific information is anecdotal or has been collected indirectly during studies of
other species (McCubbing 2002, Trotter 2008). The diverse array of habitats occupied by
CCT and the varied life history strategies displayed by the species have added to the
challenges in extrapolating range-wide trends from the research that has been conducted.
For these reasons, watershed-specific, or at least regional evaluations of CCT are required to
assess and manage stocks appropriately. This is of particular importance in British Columbia,
which contains the majority of the species native range. To date, however, the research on
the migration patterns and movement behaviours of CCT has occurred overwhelmingly at
the extremities of the species range (specifically, in Oregon and Alaska).
Coastal Cutthroat Trout of the Kitimat Watershed
The Kitimat River flows into Douglas Channel near the town of Kitimat, on the
northern coast of British Columbia. The geography, flora and fauna of this medium sized
coastal watershed have attracted industry and recreationists for decades. Heavy industrial
developments have been occurring in the lower Kitimat River and estuary since the 1950’s.
The watershed has also experienced extensive forest harvesting, much of which occurred
prior to the development of harvesting guidelines designed to mitigate impacts on
salmonids (Karanka 1993). The unique geographic features that initially attracted industry
to Kitimat continue to do so and multiple major energy projects are currently in the
11

proposal and development phases. Despite the extensive industrial activity, artificial
supplementation has contributed to an abundance of Pacific salmon which draw
recreational anglers from around the world. Coastal cutthroat trout are captured as bycatch during salmon fisheries and are targeted by local recreational anglers throughout the
winter and spring. Though not as popular as the salmon fishery, the life cycle, behaviours
and population structure of CCT make them increasingly vulnerable to angling and industrial
activity (Slaney and Roberts 2005). The development of major energy projects in the
watershed is likely to impact local salmonid populations by directly affecting habitat
connectivity and quality, and indirectly by increasing infrastructure and the local population
base.
Identifying the best means of mitigating further impacts to CCT in the face of
continued development within the watershed requires a thorough understanding of the
subspecies’ movements, behaviours and habitat use. This research will contribute to our
knowledge of the basic life history and ecology of CCT in the northern portion of this
subspecies geographic distribution, and should thus contribute to regional fisheries
management and conservation efforts.
My objective was to describe the observed variation in overwintering, staging and
spawning behaviours for CCT in the Kitimat watershed. I used radio telemetry to examine
the distribution of overwintering and spawning areas throughout the watershed, but also to
determine the timing of CCT movements throughout the winter, staging and spawning
periods. This approach allowed me to determine timing of departure from and arrival to,
overwintering and spawning habitats. This research, will contribute to our knowledge of the
12

basic life history and ecology of CCT in the central/northern portion of the species
geographic distribution.
METHODS

Fish Capture, Sampling and Radio Tagging
Coastal cutthroat were captured by angling throughout the Kitimat watershed over
two sampling seasons, from August to mid-December of 2012 (year 1) and from June to
mid-October of 2013 (year 2). Angling effort was widely distributed throughout the Kitimat
watershed to ensure a diverse array of fluvial and diadromous life history strategies would
be included in the radio tagged sample. Angling effort was primarily focused on mainstem,
side-channel and major tributary habitats believed to support fluvial and diadromous CCT.
Angling effort (rod hours), pH, water temperature, air temperature, location (UTM) and
habitat type (i.e. pool, riffle, glide) were recorded at each sampling location.
Upon capture, all fish visually identified as coastal cutthroat trout were placed
within a black PVC recovery bag and were kept at the site of capture until angling was
complete. All sampling was conducted in the field and regardless of size all captured CCT
were photographed, measured for fork length (mm) and weight (± 5 g) determined using a
calibrated spring scale. Scale and tissue samples were also collected from CCT greater than
100 mm in length. Scales were collected from the left side of the fish, above the lateral line
and slightly posterior to the distal insertion of the dorsal fin and were stored within
adhesive scale envelopes for age determination by Birkenhead Scale Analyses (Lone Butte,
BC). Tissue from the adipose fin was collected for genetic analysis and stored in 95%
ethanol. To ensure that sampled fish were not mistaken for hatchery released fish the
13

natural shape of the adipose fin was maintained as much as possible. Tissue samples were
used for genetic determination of sex as well as species diagnostic testing to identify
potential hybrids. Analysis was performed by AB Costello (University of Northern British
Columbia). A uniquely numbered Floy™ tag was also inserted between the vestigial rays at
the base of the dorsal fin in all CCT greater than 250 mm.
Ninety uniquely coded Lotek® MCFT2-3EM series radio transmitters (Lotek Wireless
Inc., New Market, ON) were surgically implanted into the intraperitoneal cavity of CCT
greater than 440 g. Tags were 12 mm x 53 mm, weighed 11 g in air and 4.6 g in water with a
43-cm antenna. To reduce collisions, each tag was programmed with either a 5 or 5.5 s
burst rate and a frequency of either 150.350 MHz or 151.700 MHz. Expected battery life for
all MCFT2 type transmitters was 423 d. Additionally, ten smaller radio transmitters were
implanted intraperitoneally into CCT greater than 250 g during the 2013 sampling season
(Lotek® MST-930 series). These tags were 9.5 mm x 28 mm and weighed 4 g with a 37.5 cm
whip antenna. The smaller tags also had a 5.5 s burst rate with an expected battery life of
222 d, and transmitted at 150.350 MHz. The predefined weight limits ensured that the dry
weight of radio tags was no greater than 2.5% of the total weight (in air) of CCT. Though this
is outside of the generally followed "2%-rule" (Winter 1983), it is consistent with previous
radio telemetry studies of cutthroat trout where tags less than 2.5% were implanted
(Waters 1993; Hendricks 2002; Goetz et al. 2013; Smircich and Kelly 2014).
Coastal cutthroat trout selected for surgery were anaesthetized in a 30 L tote with
oxygenated river water containing 50 mg · L–1 clove oil emulsified in ethanol. A general loss
of reactivity to external stimuli and slightly decreased opercular rate were used to assess
14

depth of anaesthesia (Stage 2, Summerfelt and Smith 1990; Brown et al. 2008). Upon
reaching the fourth stage of anaesthesia fish were removed from the anaesthetic bath and
placed within a custom LEXAN™ plastic surgical trough lined with wetted closed cell foam
(Summerfelt and Smith 1990; Brown et al. 2008).
A 2-cm incision was made anterior to the pelvic girdle and lateral to the midline. A
cannula was then inserted into the peritoneal cavity through the incision and positioned
such that it exited posterior to the pelvic girdle. The antenna of the radio transmitter was
fed through the cannula and the transmitter was inserted into the peritoneal cavity. Two
sutures (3-0, 26 mm 1/2c Tapered Monocryl violet monofilament) were used to close the
incision and the fish was immediately transferred to a recovery tote containing 35 L of river
water oxygenated with a portable aquarium air pump. A turkey baster was used to apply
fresh oxygenated water to the gills throughout the entire surgical procedure. The duration
of each surgery was timed from the moment the fish was removed from the anaesthetic
until the moment it was returned to the recovery tote. Surgeries ranged in duration from
145 to 702 s with a mean and standard deviation of 307 ± 106 s. Once equilibrium was
regained and the fish appeared to respond to external stimuli it was transferred from the
recovery tote to the black PVC recovery bag at the location of capture. When the fish
appeared vigorous, the recovery bag was opened and fish released.
Relocation of Radio Tagged CCT
Movements of radio tagged CCT were monitored using a combination of active and
passive relocation techniques. The positions of radio tagged CCT were identified via aerial
and ground based searches. Fixed receiver sites were erected at key points throughout the
15

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habitats were searched at a single point in time. The relocation snapshot provided by aerial
tracking is also beneficial as it provides greater insight into how individuals have responded
to changes in their environment than could be achieved through ground based or passive
search techniques. For these reasons, active tracking by helicopter was the primary means
of relocation throughout the key periods of interest in this study: the winter and spring.
A total of 32 aerial tracking flights were completed with a Bell 206 Jet Ranger
mounted with a single 3-element Yagi antenna (Lotek Wireless Inc.). This antenna was
connected to two SRX-400 Receivers (Lotek Wireless Inc.), each of which monitored one of
the two transmitter frequencies. The time on the receivers was synchronized to the time on
a Garmin 60CSx handheld Global Positioning Systems unit (GPS) (Olathe, KS) which recorded
a track of the helicopters position at 1 s intervals. To determine relocation positions, the
time at which the maximum signal power was recorded was matched to the time of the
recorded flight track. For redundancy, the maximum power and helicopter position at the
time of maximum power was also physically recorded as a waypoint on the GPS.
Relocation flights followed a standardized flight path that covered the mainstem of
the Kitimat River and its major tributaries. However, throughout the spawning period short
deviations from this path were required to identify spawning positions in small tributaries.
Tracking flights ranged from 1.2 to 3.5 h (mean 2.5 ± 0.09 h) and were relatively shorter
during the winter (mean 2.0 ± 0.09 h) than during the spawning period (mean 2.8 ± 0.8 h).
Active aerial tracking occurred at altitudes of roughly 100-200 m and at speeds from 30-60
km/h. During all tracking flights signal power was communicated to a navigator who
directed the pilot. To improve tracking efficiency, Avenza PDF Map’s (Toronto, ON) was
17

used to display the last known positions of all CCT on a georeferenced orthorectified
satellite image of the Kitimat watershed. To determine the type and characteristics of
relocation habitats a GoPro® (San Mateo, CA) camera was mounted to the helicopter and
filmed and photographed throughout the flights.
The frequency, duration and scale of relocation flights reflected the predicted
seasonal behaviours of CCT. When CCT were expected of being sedentary throughout the
winter, tracking flights were conducted monthly and focused primarily on the mainstem of
the Kitimat River and its major tributaries. In the spring as CCT moved to spawning habitats
the frequency of tracking flights increased to every 4-8 d and scale expanded to include
both minor tributaries and uppermost reaches of the Kitimat watershed.
Throughout the late winter and spring, tracking flights were supplemented with
daily ground based mobile tracking. Mobile tracking was primarily used to monitor the
timing of movements out of overwintering habitats, confirm aerial relocation positions,
verify suspected spawning areas, and recover radio transmitters from mortalities. A 3element directional antenna connected to an SRX-400 was used to triangulate positions
which were then marked using a handheld GPS device. Relocation habitat types were
recorded and photographed. During the spawning period, the vicinity was visually searched
for signs of spawning (i.e. redds, spawning gravels, paired up CCT, precocious males). No
formal habitat classification or measurements were conducted throughout this study.
Active aerial and ground based search methods were necessary to identify where
CCT travelled throughout the watershed however they provided limited information on

18

when individuals moved between habitats. Insight into the timing of movements between
habitats was provided by an array of stationary receivers set up throughout the watershed.
These receivers provided information on the timing of movements out of overwintering and
spawning habitats as well as the timing of movements towards the estuary.
Four fixed receivers were erected along the Kitimat River in Mid-August of 2012 and
a fifth station was added in early April of 2013 (Table 1.2). Each receiver location consisted
of an upstream and a downstream facing 4-element directional Yagi antenna connected to a
Lotek SRX-400 receiver and powered by a 12 V deep cycle marine battery. Receivers were
housed within a secure steel box mounted to a tree along the margin of the Kitimat River. A
GPS unit was used to synchronize the date and time of all stationary receivers. Receiver
stations operated continuously and recorded the date, time, code and power of all
relocation events. Movements to and from the Kitimat Estuary were monitored by a
receiver station immediately upstream of the tidal boundary (2.8 rkm). Movements within
the lower and middle river were monitored by receiver stations at 8.2 rkm and 16.1 and
25.1 rkm, respectively. The uppermost receiver station was located at 41.7 rkm and
monitored the timing of movements to and from the upper watershed.
All receiver stations were erected in August of 2012, except the receiver at 2.8 rkm,
which was erected in April of 2013. Receivers were inspected, downloaded and maintained
weekly. Logistical challenges associated with access and maintenance of stationary
receivers prevented continuous operation throughout the winter, except for the receiver
station at 8.2 rkm which was graciously operated with the support of the DFO operated
Kitimat River Fish Hatchery. Excluding the station at 8.2 rkm which operated until July 23,
19

2014, all receiver stations were dismantled on June 1, 2014. Table 1.2 provides a summary
of the periods of operation for each receiver station. Lotek SRX-400 receivers and telemetry
equipment were provided by the BC Ministry of Forests, Lands and Natural Resource
Operations (FLNRO).

Table 1.2. Summary of location and operation period of stationary receiver stations in the Kitimat watershed.

Receiver # rkm Year
1
2

Operation Period

00

2.7

02-Apr-13 to 10-Oct-2013
31-Mar-14 to 01-Jun-2014

01

8.7 1 & 2 16-Aug-12 to 23-Jul-2014

02

16.5

1
1
2

19-Aug-12 to 19-Dec-2012
01-Mar-13 to 06-Oct-2013
24-Mar-14 to 30-May-2014

03

25.1

1
2

19-Aug-12 to 06-Oct-2013
21-Mar-14 to 20-May-2014

04

41.7

1
1
2

19-Aug-12 to 15-Dec-2012
06-Feb-13 to 16-Oct-2013
21-Mar-14 to 01-Jun-2014

Data Processing and Analysis
Relocation accuracy to within 500 m was deemed sufficient to meet the objectives
of this study. Thus, no direct measure of the accuracy of aerial relocation positions were
conducted. Ground based mobile tracking, however, confirmed that actual fish positions
were typically within 100 m, and often within 10 m, of the aerial relocation positions.
Positions identified by mobile tracking were similarly not tested for accuracy as only the
strongest signals were used to identify relocation positions.

20

Greater than 1.3 million detections were recorded by the fixed receiver stations
throughout this study. To filter out weak and potentially erroneous detections a set of rules
were applied to the fixed station (Table 1.3). These rules were applied to all detections of a
specific code by a specific receiver on a single date, if any rule was met the relocation event
for that date was included in the analysis. Overall these rules reduced the number of
detections included in the analysis by approximately 42%.
Table 1.3. Summary of tests applied to stationary receiver data to remove potential erroneous detections.
Test of:

Test #

Signal Power

1
2
3

Average power greater than 175 and more than 10 detections in a day.
Maximum power is greater than 195 and there are greater than 25 detections in a day.
Average power is greater than 120, maximum power is greater than 200 and at least 10 detections in a day.

Description

# Relocations

4
5

Greater than 500 events in a day and average power is greater than 110.
Greater than 250 events in a day and average power is greater than 130.

% of Possible
Relocations

6
7

At least 25% of the possible detections were recorded over a 1 hour time period and the average power is 140.
Fish relocated at least 20% of the time over a period of at least 20 minutes and the average power is greater than 120.

The Linear Referencing toolset in ArcMap 10.1 (ESRI, Redlands, CA) was used to
assign each relocation event to the nearest stream (Euclidean distance) in the British
Columbia Watershed Atlas. The same toolset in ArcMap was then used to measure the
linear distance (measured in river kilometers, rkm) of the relocation position from the
estuary along the stream network. This method permitted an accurate and consistent
means of determining the position of each CCT within the stream network. Measurements
of mainstem position (rkm) were measured upstream from the estuary (0 rkm) while
measures of tributary position (tkm) were measured upstream from the confluence with
the last major watercourse. A database was developed in a spreadsheet that used these
measures of rkm and tkm to calculate the distance that individuals moved between
relocations. This resulted in a final spatial dataset that included the date and position (in
21

terms of waterbody, rkm and tkm) for each relocation event of each fish within the
watershed as well as the distance each individual had travelled since it was last relocated.
Two datasets were generated for this study: a biological dataset containing all fish
sampling information and a spatial dataset containing the measured relocation positions of
all radio tagged CCT. Together, these datasets were used to interpret the variation in
observed seasonal behaviours of radio tagged CCT. Prior to performing any analyses on the
behaviours of CCT, the metrics within the biological dataset were compared between
sampling seasons to ensure that CCT radio tagged in 2012 and 2013 were similar in terms of
the distribution of sex, age, fork length, weight and contribution. The relocation data was
used to generate movement profiles depicting the river and tributary position of each radio
tagged CCT over time. These profiles were visually inspected to identify the location of, as
well as the timing that CCT occupied overwintering, staging and spawning habitats. The
spatial dataset was then used to summarize the movements and behaviour of CCT within
each of these habitats. Coastal cutthroat trout exhibiting similar behavioural patterns were
grouped and analysed in greater detail.
Overwintering Behaviours
The locations of overwintering areas were identified by examining movement
profiles and identifying areas where CCT aggregated throughout the winter. The position
(rkm and tkm) of each overwintering area was defined as the mean relocation position of all
aggregated CCT. Movements of CCT within and between overwintering habitats were also
summarized to assess variability in winter behaviours. For each CCT relocated within a given
overwintering area, the date of arrival and departure, and distance travelled to mean
22

overwintering position was calculated. An individual’s date of arrival and departure from a
given overwintering area was defined as the first and final date of relocation, respectively
(measured in Julian date). The distance travelled towards initial overwintering areas was
calculated as the difference in position from the location of capture to the mean position of
the first overwintering habitat each CCT was observed within. This approach reduced
contact bias resulting from an unequal number of relocations among CCT by ensuring that
all measures of distance moved towards an overwintering area were not based upon a
single relocation event. Distance travelled between overwintering habitats was measured as
the difference between the mean river position of each habitat. Based on these
overwintering behaviours, CCT were classified as stationary if they occupied a single
overwintering area throughout an entire winter or as mobile if they moved between
multiple overwintering areas throughout the winter. The resulting overwintering behaviours
dataset was then merged with the morphological dataset to examine whether the physical
characteristics of CCT differed among overwintering groups. This merged dataset was used
to complete a set of independent tests examining variability in overwintering behaviours.
These tests aimed to identify whether the date of arrival and departure from overwintering
habitats and the distance travelled to initial overwintering habitats differed between years,
sex or behavioural groups.
Staging Behaviours
Radio tagged CCT observed moving from overwintering areas to a location
downstream of eventual spawning habitats were assumed to be staging prior to spawning.
Individuals observed moving back and forth between staging habitats and the lower reaches
23

of spawning tributaries were considered to be searching. These individuals were not
considered to have departed staging habitats until they were observed making continuous
upstream movements towards eventual spawning grounds. The date of arrival and
departure as well as distance of staging habitats from overwintering areas and to maximum
upstream spawning positions was calculated for each staging CCT.
Spawning Behaviours
Movement profiles of each CCT were visually inspected to identify period and
location of spawning. Spatial data were then used to define position of spawning habitats
and summarize behavioral characteristics of all CCT observed moving into tributaries
throughout the spawning period. This summary provided a means of capturing spatial and
temporal variability in spawning behaviours among individual CCT as well as among CCT
using common spawning grounds. No radio-tagged CCT were visually observed on redds
throughout the spawning period. Thus, each individual is assumed to have spawned at the
location of, and on the date corresponding to, the maximum upstream relocation position
within a putative spawning tributary. This approach is warranted given that the spawning
behaviours observed during this study (i.e. direct movements into small tributaries
throughout the spring) coincide with findings from previous research on coastal cutthroat
trout. A similar technique was recently applied by Homel et al. (2015) to identify the timing
and location of spawning west slope cutthroat.
Temporal variability in spawning behaviours was quantified by defining the period
during which each CCT spawned. The spawning period for each CCT was defined by date of
arrival, date corresponding to maximum upstream relocation position, and date of
24

departure from a putative spawning tributary. Date of arrival in a putative spawning
tributary was defined as the first relocation date immediately prior to continuous upstream
movement towards the maximum upstream tributary position. Spawning was assumed to
have occurred on the date a CCT was observed in its most upstream position within a
supposed spawning tributary. Date of departure from spawning habitats was defined as the
last date on which CCT were relocated within their assumed spawning tributary. Individuals
that were only relocated once in a single tributary throughout the spawning period are
assumed to have arrived, spawned and departed on the date of that relocation. These three
temporal measures were then used to define the duration CCT travelled to reach spawning
habitats as well as the median date of arrival and spawning (max tkm).
In addition to the temporal measures, spatial metrics were calculated for each CCT
observed in a spawning tributary. Spatial measures aimed to quantify the distances CCT
travelled to reach spawning habitats as well as to examine the relationship between
location of capture, overwintering, staging and spawning habitats. Distance travelled to
spawning habitats was calculated as the difference in river position from the maximum
upstream spawning position to the mean position of a given overwintering area. For mobile
CCT, this distance was measured from initial and final overwintering habitats to examine
whether mobile CCT selected initial overwintering habitats that were proximal to spawning
tributaries and whether movements throughout the winter reduced the distance to
eventual spawning grounds. Similarly, distances from capture and staging habitats were
measured as the difference in river position from the maximum upstream spawning
position to the location of capture and the mean staging position.
25

Variability in these spatial and temporal measures of spawning behaviours were
analyzed using numerous independent tests. The distance travelled to spawning habitats as
well as the date that CCT arrived in spawning tributaries and at their maximum upstream
tributary position were compared between years, sexes and migration types. Similarly,
these same tests were performed on all CCT within a spawning season period.
Statistical Analyses
Welch’s two-sample t-test was used to test for differences in physiological measures
between sampling periods, behavioural groups and sexes. The same test was used to
examine how the magnitude of movements from capture to overwintering habitats as well
as from overwintering habitats to staging and spawning habitats differed between sexes,
behavioural groups and years. No tests of homogeneity of variance were conducted on
comparisons of two groups as Welch’s two-sample t-test is robust to heterogeneity in
variance between groups.
Variation in the timing of behaviours was examined using a two-sample KolmogorovSmirnov test. This test compared the distribution of dates that CCT arrived in and departed
from overwintering, staging and spawning habitats. Radio tagged CCT were assumed to
have remained within a habitat until they were relocated elsewhere. Spawning was not
observed during this study and is assumed to have occurred on the date corresponding to
the maximum upstream tributary position. Spawning departure dates are defined as the last
date each CCT was observed within a tributary. Radio tagged CCT observed making
downstream movements towards the estuary immediately following spawning are assumed
to be sea-run and are to have arrived in and departed from the estuary on the date
26

corresponding with the last, and first relocation on the most downstream fixed receiver
station, respectively. A Spearman correlation test was used to examine the relationship
between capture date and the physical characteristics of radio tagged CCT.
Measures reporting the overall timing of seasonal movements are presented as the
date at which 50% of CCT were observed to have moved (median ± standard deviation).
Additional descriptive measures are presented as the sample mean ± standard error along
with the range of raw values. This approach is preferred as it demonstrates the degree to
which the sample mean can be expected to vary from the true population mean. Measures
of range are included to provide perspective on the spread of values in the dataset. Tests
with alpha values less than 0.05 were considered significant. However, to reduce type 1
error, a Bonferroni correction was applied to significance values when multiple comparisons
were made with the same dataset. Tests found to be statistically insignificant but for which
there appears to be a biological significance or trend are presented. All significant test
results are presented in bold.
RESULTS

Fish Collection Effort
Angling was conducted over a 54-day period from August 8 to December 15, 2012
(year 1) and over a 72-day period from June 20 to October 18, 2013 (year 2). A total of 258
trout were sampled during angling in year 1 (n = 103) and 2 (n = 155). Of these, 41 trout
angled in year 1 and 68 trout angled in year 2 were of suitable size to be radio tagged.
Throughout the first and second sampling season a mean of 0.76 and 0.94 CCT were radio
tagged per day of angling, respectively. The date on which 50% of tags had been deployed
27

was significantly later for the first year of sampling (October 8) than for the second
(September 7) (Two Sample KS Test, Ho: Year 1 > Year 2; D = 0.43, P = 0.002).
Angling effort was widely distributed throughout the lower 50 rkm of the watershed
(Figure 1.2). Coastal cutthroat trout selected for radio tagging were angled in the estuary (n
= 1), the lower river (from 0-21 rkm; n = 39), the middle river (21-41 rkm; n = 47) and the
upper middle river (>41 rkm; n = 15) (Table 1.4). Cutthroat trout selected for radio tagging
were also captured in tributaries in year 1 (n = 13, 13% of sampled CCT) and year 2 (n = 33,
21% of sampled CCT).

Figure 1.2. Histogram comparing the location that radio tagged CCT were sampled throughout the Kitimat
watershed.

28

Table 1.4. Mainstem river position (rkm) of radio tagged CCT at capture in year 1 and year 2.

Water Body

rkm

Kitimat River Mainstem
Lower Mainstem 0 – 20.9
Middle Mainstem 21 – 40.9
Upper Mainstem
> 41
Estuary
Duck Creek
Goose Creek
Hirsch Creek
Powerline Creek
Little Wedeene Creek
Big Wedeene Creek
Nalbeelah Creek
Humphrey Creek
Total:

0
10.6
10.8
15.7
16.5
20.1
21.4
24.8
29.7

Number of Radio Tagged CCT
Year 1
Year 2
25
5*
13
7

36
4*
22*
10**

0
1
1
4
2
1
2
1
4

1
1
3
9
0
8
4
3
1

41

66

* Tally of the number of trout exhibiting genetic markers uncharacteristic of
pure CCT included in summary.

Sampled CCT
Sampled coastal cutthroat trout ranged in length and weight from 110 to 480 mm FL
(325 ± 4 mm FL) and 35 to 1180 g (464 ± 17 g), respectively (Table A1.12; Figure A1.1A and
B). Age was estimated from the scales of 205 CCT ranging in size from 135 to 480 mm and
35 to 1120 g. The mean age of all sampled individuals was 3.8 ± 0.8 years, though estimates
ranged from 2 to 7 years (Figure A1.1C). Genetic analysis was performed on 241 samples
and identified that female CCT were sampled disproportionately relative to males. Indeed,
females represented 64% of all sampled CCT. Female CCT were found to be significantly
longer, heavier and older than male CCT (Table A1.1). Even though females were

2

Table and figure references in appendices are denoted by “A”.

29

significantly larger than males, no difference in condition factor was apparent between the
sexes (Table A1.1; Figure A1.1D). A fork length frequency distribution for all sampled
cutthroat is presented in Figure 1.3.

Figure 1.3. Fork length frequency histogram of all CCT captured in 2012 and 2013.

30

Radio Tagged CCT
A total of 99 CCT were implanted with the larger radio transmitters during sampling
in year 1 (n = 41) and year 2 (n = 58). Six radio transmitters recovered from spawning
mortalities during the spring of year 1 were reapplied to trout captured during the second
sampling season. An additional three transmitters collected from CCT that died during tag
implantation in year 2 were sterilized and reapplied.
Fork length and weight of CCT implanted with the larger tags ranged from 330 to
480 mm (385.6 ± 4.4 mm) and 430 to 1180 g (671.6 ± 20.5 g), respectively (Table A1.2;
Figure 1.4A and B). Overall, radio transmitters represented a mean of 1.78 ± 0.05 % of the
dry weight of these CCT, though this ranged from 0.93 to 2.62%. Scales from 96 radio
tagged CCT were aged and fish ranged from 3 to 7 yr; mean age of 4.2 ± 0.1 yr (Figure 1.4C).
Genetic analysis of the radio tagged CCT indicated that 66% were female; a ratio that was
consistent in both sampling years. Coastal cutthroat trout tagged in year 1 were longer (FL)
and heavier than CCT tagged in year 2. Despite being larger, CCT tagged in the first sampling
season had significantly lower condition factor than those tagged in year 2 (Figure 1.4D).
Differences in size of fish caught in the two years of the study were principally driven
by the size of males; which were significantly longer and heavier in year 1 than year 2.
Female CCT radio tagged during both sampling periods were older and heavier than radio
tagged male CCT, but differences were not significant (Table A1.2; Figure 1.4A and B).
Females in year 1 were significantly younger than in year 2 (Table A1.2; Figure 1.4C), and;
males in year 1 had significantly lower condition factor than in year 2 (Figure 1.4D).

31

In year 2, an additional 10 CCT implanted with the smaller radio transmitters were
between 3 and 5 years of age (3.7 ± 0.2 yr) and ranged in length from 276 to 355 mm (314.8
± 8.9 mm). The weight of these CCT ranged from 250 to 470 g (mean = 329 ± 53.1 g), and
transmitters represented between 0.86 to 1.60% (1.27 ± 0.08%) of the dry weight of these
CCT. Condition factor ranged from 0.87 to 1.33 g · cm–3 (1.05 ± 0.04 g · cm–3). There was
also a female biased sex ratio in the smaller tagged fish (67% female).
Of the 109 radio tagged CCT a total of 19 (18% of total tagged) likely expelled their
transmitters or died shortly after the tagging procedure, including three CCT that died
during the operating procedure in year 2. In the second sampling period, six CCT (6% of total
tagged) moved directly to the estuary after being radio tagged and were not subsequently
relocated. Though the fate of these individuals is unclear they are presumed to have died.
Additionally, three CCT (3%) appear to have died after moving into overwintering habitats in
year 1 (n = 1) and year 2 (n = 2). An additional eight CCT (7% of total tagged) were not
relocated – or were relocated sporadically following tagging in year 1 (n = 2) and year 2 (n =
6). In total, this represents a potential tagging mortality rate of up to 34% for all radio
tagged CCT.
The physical characteristics and fate of all radio tagged CCT, and the timing and
physical state of recaptured radio tagged CCT are summarized in Table A1.3 and Table A1.4,
respectively. The physical condition of radio tagged CCT that were recaptured during
subsequent sampling are described in Appendix A1. Supplemental Recapture Data.

32

A

C

B

D

Figure 1.4. Fork length (A), weight (B), age (C) and condition factor (D) of male and female CCT radio tagged
with large transmitters in year 1 and year 2.

33

Overwintering Behaviours
A total of 68 radio tagged CCT were relocated in overwintering habitats and were
successfully tracked throughout the winters of year 1 (n = 31) and year 2 (n = 37). Forty-two
of the CCT tracked throughout the winter were observed moving from their position of
capture into overwintering areas. The remaining 26 CCT were captured and radio tagged
within overwintering areas, 17 of which eventually moved to new overwintering habitats at
a later date. The number of CCT captured in overwintering habitats did not differ between
years, even though sampling occurred significantly later in year 1. Six CCT radio tagged in
year 1 were observed in overwintering areas during both winters (Table A1.5). An additional
11 CCT were tracked into overwintering areas, but were not relocated sufficiently to be
included in further analyses.
Two distinct behavioral patterns were apparent in the winter movement profiles of
CCT that were tracked throughout the winter. The first behavioral pattern was one of
relative inactivity. These “stationary” CCT remained within the immediate vicinity of a single
overwintering area throughout the winter. Stationary CCT were observed during both
winters, however this behaviour was far more prevalent in year 1 (n = 19) than year 2 (n =
6). The second behavioral pattern was characterized by movement between multiple
overwintering aggregation areas throughout the winter. “Mobile” CCT were observed
moving between proximal habitat features within overwintering areas (i.e. adjacent riffles
and pools), back and forth between overwintering areas as well as continuously moving
towards new overwintering areas.

34

When data from both years was combined, stationary CCT were found to be
significantly longer and heavier than mobile CCT (Table A1.6; Figure 1.5A and B). Although,
the mean age of stationary fish was also older, the difference was not significant (Figure
1.5C). Additionally, condition factor did not differ between behavioural groups, although
condition factor of mobile CCT was significantly greater in year 2, than year 1 (Figure 1.5D).
Six female CCT radio tagged in year 1 were relocated in overwintering areas during
both winters; four of which were tracked sufficiently to determine overwintering
behaviours for both years. Throughout the winter of year 1, four of the six CCT exhibited
stationary behaviours and two exhibited mobile behaviours. During the following winter,
however, one of the four year 1 stationary CCT was observed moving between overwinter
areas in year 2. Two of the three CCT that displayed stationary behaviours during both
winters occupied the same overwintering areas in year 1 and 2 (ID#009 and ID#013), while
the third remained stationary in each year, but in different overwintering habitats (ID#050).
The movement behaviours of these CCT are summarized in Table A1.5

35

A

B

C

D

.

Figure 1.5. Fork length (A), weight (B), age (C) and condition factor of mobile and stationary CCT tagged with
large transmitters in year 1 and 2.

36

Overwintering Areas
Tracking of radio tagged CCT identified nine areas where CCT aggregated in the
Kitimat watershed (Figure 1.6). Overwintering areas were located in the lower and middle
sections of the Kitimat watershed, from 10 to 35 rkm (Figure 1.7). No radio tagged CCT were
observed upstream of 35 rkm from mid-December until late March of either winter.
Overwintering aggregations were identified in the mainstem of the Kitimat River, the lower
reaches of major tributaries and within sloughs and back channels associated with minor
tributaries. Deep, slow moving pools and backchannel sloughs were used most commonly,
however radio tagged CCT were frequently relocated within adjacent riffles and glides. The
position of initial (Figure 1.7) and final overwintering habitats (Figure 1.8) did not differ
significantly between years, sex (Table A1.7), or behavioural groups (Table A1.8).

37

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!
.@VHB>!M:]:!NEC@D@E?!EF!X@?D>B!JVVB>VJD@E?!JB>JC!1B>U!UEDC2!HC>U!89!BJU@E!DJVV>U!//0!@?!D=>!3@D@IJD!XJD>BC=>U:!!

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Figure 1.7. Mean river and tributary position of initial overwintering habitats used by radio tagged CCT in year
1 and 2. Note that northern and southern tributaries are identified by positive and negative values of tributary
position, respectively.

Figure 1.8. Mean river and tributary position of final overwintering habitats used by radio tagged CCT in year 1
and 2. Note that northern and southern tributaries are identified by positive and negative values of tributary
position, respectively.

39

Timing of Arrival in Initial Overwintering Areas
The timing that CCT first moved into overwintering habitats was estimated using
relocation and capture data. Relocation data suggested that half of all CCT radio tagged in
year 1 had been relocated within overwintering areas by November 20, significantly later
than the median date of arrival in year 2 (October 21). When data from both years was
combined, no differences were observed in the date that CCT were captured in
overwintering habitats between sexes (Table A1.9; Figure 1.9A) or winter behavioural
groups (Table A1.10; Figure 1.10A). Median dates of arrival in overwintering areas,
however, directly corresponded with the date of the first aerial tracking flights during each
winter (Figure 1.9B and Figure 1.10B). Thus, it is likely that the median arrival dates
observed in this study are not only conservative, but that they were biased by the sampling
design and aerial tracking frequency. This is particularly true for the first winter, as minimal
sampling was conducted throughout October and the first flight was not conducted until
November 20, 2012.
Given this bias, the relocation data was combined with the angling data to gain
additional insight into when CCT arrived in overwintering areas. This provided a means of
indirectly assessing arrival timing by examining the relationship between the relative
proportion of CCT that had been radio tagged to the total number of radio tagged CCT
observed and captured within overwintering habitats. Figure 1.11 demonstrates that the
relative proportion of CCT captured within overwintering habitats increased steadily from
late October of year 1, and from mid-October of year 2, suggesting that CCT may have
moved into overwintering habitats earlier than the dates identified by aerial tracking flights.
40

A

B

Figure 1.9. Date that male and female CCT were captured within (A), and first relocated within (B), initial
overwintering habitats in in year 1 and 2. Note CCT that were captured in overwintering habitats are not
included in Figure 1.9A.

A

B

Figure 1.10. Date that mobile and stationary CCT were captured within (A), and first relocated within (B), initial
overwintering habitats in in year 1 and 2. Note CCT that were captured in overwintering habitats are not
included in Figure 1.10A.

41

Figure 1.11. Comparison of the relative proportion of radio tagged CCT (dotted line) that were observed (solid
line) and captured (dashed line) in overwintering habitats in year 1 and 2. The dates when aerial relocation
flights were conducted are indentified by circles. The median date when radio tagged CCT were observed
within overwintering habitats in each year is identified by an “X”. Note that the relative proportion of CCT
observed within overwintering habitats (dashed line) includes CCT that travelled to overwintering habitats, as
well as CCT that were captured within overwintering habitats.

42

Travel to Initial Overwintering Areas
Excluding the 27 CCT that were captured within initial overwintering areas, radio
tagged trout were observed traveling up to 22.0 rkm and up to 12.0 tkm from their location
of capture to initial overwintering areas (Table A1.11 and Table A1.12). When the data from
both years were combined female CCT travelled significantly further than males through the
mainstem (rkm) as well as in total when mainstem and tributary distances were combined
(Table A1.11; Figure 1.12A and Figure 1.13A). When sex data in each year was combined,
CCT travelled further in year 2, through the mainstem as well as in total, although the
differences were not statistically significant. The apparent difference was likely driven by
males in year 1 which were captured closer to OW habitats than females in year 1, and
males in year 2. Distances travelled to overwintering habitats did not differ between mobile
and stationary CCT during either year, or when years were combined (Table A1.12; Figure
1.12B and Figure 1.13B). Nor were differences apparent between years when behavioural
groups were combined.

43

A

B

Figure 1.12. Mean and SE absolute distance male and female (A), and mobile and stationary (B) CCT travelled
through the mainstem from their location of capture to initial overwintering habitats in year 1 and 2.

A

B

Figure 1.13. Mean and SE absolute distance male and female (A), and mobile and stationary (B) CCT travelled
through the mainstem and tributaries from their location of capture to initial overwintering habitats in year 1
and 2.

44

Movement Between Overwintering Habitats by Mobile CCT
Stationary CCT were only observed within a single overwintering location. In
contrast, mobile CCT moved between 2 to 5 overwintering habitats from November 20 to
March 21. The number of CCT in mainstem overwintering aggregations generally increased
throughout the winter (Figure 1.14). Mobile CCT travelled total distances of up to 15.0 km
between overwintering habitats and both up- and downstream movements were observed.
Final overwintering positions were a mean distance of 1.7 ± 0.7 km downstream of initial
overwintering habitats, though final overwintering positions were observed as far as 12.0
km up and downstream of initial overwintering locations. Males tended to move between
more overwintering habitats than females in year 1 and females tended to move between
more habitats than males in year 2. However, the mean distance CCT travelled between
habitats did not differ statistically between sexes or years, nor were differences apparent in
the total distance CCT travelled throughout the winter (Table A1.13). Cutthroat moving
between more overwintering habitats did not necessarily move greater total distances
throughout the winter. Indeed, male CCT occupied relatively, but not significantly, more
habitats in year 1 than year 2, yet no difference was observed in the total distance travelled
between years.

45

Figure 1.14. Mean river position of overwintering aggregation areas in the Kitimat watershed in year 1 and 2.
The size of each point corresponds to the number of fish observed within each overwintering area. Initial
overwinter (OW) areas represent the first overwintering habitat that mobile and stationary radio tagged CCT
were observed within. The three lower panels represent the position of the second, third and fourth
overwintering habitats used by mobile CCT, and thus demonstrate how the distribution of mobile CCT changed
over time. Note that northern and southern tributaries are identified by positive and negative values of
tributary position, respectively.

46

Departure from Overwintering Habitats
Radio tagged CCT departed overwintering habitats from early March to early May.
Greater variability in departure times was observed between years than between sexes or
behavioural groups. Indeed, departures occurred significantly earlier in year 1 than year 2
when movements of all CCT were considered as a whole, regardless of sex (Table A1.14) or
behaviour group (Table A1.15). A strong negative correlation was observed between the
date that CCT departed overwintering habitats and the total distance travelled to reach
spawning habitat (Figure 1.15).
From overwintering areas, radio tagged CCT either moved directly into spawning
tributaries or into pre-spawn staging areas. Staging and non-staging CCT departed
overwintering habitats at similar times. Combining sex and behavioural data identified that
non-staging CCT departed overwintering habitats significantly earlier in year 1 (Figure 1.16A
and B). However, between year differences were not apparent among staging CCT (Figure
1.17A and B). Females departed overwintering habitats later than males in each year,
however differences were not statistically significant. Nor were other differences apparent
between males and females during, or between years.
Among mobile and stationary CCT, differences were apparent between years, but
not between groups. Mobile CCT departed significantly earlier in year 1 than year 2 when
staging and non-staging CCT were assessed together, but differences between years were
not statistically significant when staging and non-staging fish were considered
independently (Table A1.15). Departure times of stationary CCT did not differ between
years.
47

Figure 1.15. Correlation between the date that radio tagged CCT departed final overwintering habitats and the
total distance travelled (rkm + tkm) to spawn.

A

B

Figure 1.16. Median date non-staging male and female (A) and mobile and stationary (B) CCT departed
overwintering habitats in year 1 and year 2.

48

A

B

Figure 1.17. Median date staging male and female (A) and mobile and stationary (B) CCT departed
overwintering habitats in year 1 and year 2.

Movement from Overwintering to Staging Habitats
Radio tagged CCT travelled up to 36 km from overwintering habitats to staging
areas. Distances travelled to staging areas were more variable among behavioural groups
than between years or sexes (Table A1.16). Mobile CCT tended to travel further to staging
areas than stationary CCT, however differences between groups were not statistically
significant within, or between years (Table A1.17).
From staging areas, CCT travelled up to 14.0 km to spawn. When data from both
years were combined, stationary CCT appeared to select staging areas that were closer to
spawning habitats than mobile CCT (Table A1.16), but the large range in movement of CCT
in each movement group resulted in a lack of statistical significance. Indeed, mobile CCT
49

appeared to travel greater mean distances in each year. No significant differences were
observed between male and female CCT in the distance travelled to spawn from staging
areas, nor were differences observed between years when sex data was combined (Table
A1.17). The timing that CCT arrived in staging areas did not differ between years, nor did it
differ between sexes (Table A1.18) or behavioural groups (Table A1.19). In fact, the median
date CCT arrived in staging areas differed by only 1 day when sex and behaviour data was
combined. Female and stationary CCT arrived later than males and mobile CCT in each year,
but again differences were statistically insignificant.
However, when sex and behavioural data were combined, significant differences
were identified in the date that CCT departed staging habitats between years. Indeed,
departures occurred significantly earlier in year 1 than year 2. Departure dates did not differ
between sexes, however females consistently departed staging areas later than males
(Table A1.18). Similarly, no statistical differences were found between behavioural groups
during or between years, though relatively greater variability was observed in the departure
dates of mobile CCT than stationary CCT (Table A1.19).
Movement from Overwintering to Spawning Habitats
From overwintering habitats, staging and non-staging CCT travelled total distances
of up to 37.0 and 35.0 km, respectively, to spawn. Distances travelled to spawn did not
differ statistically between years, or between staging and non-staging CCT. Nor were
differences apparent between sexes (Table A1.20) or behavioural groups (Table A1.21)
within or between years.

50

Despite the lack of statistical significance, trends were apparent in the data
comparing distances travelled by each sex that may be biologically important (Table A1.20).
For instance, non-staging female CCT travelled further than staging females in both years,
but especially further in year 2. Distances that staging and non-staging male CCT travelled to
spawn were comparatively more variable between years; staging males travelled further
than non-staging males in year 1, but the opposite was observed in year 2.
Non-significant, but potentially biologically important trends were also apparent
when considering the distances travelled by CCT in each behavioural group (Table A1.21).
Compared to staging CCT, non-staging stationary and mobile CCT travelled relatively further
in each year. Additionally, overwintering locations used by staging and non-staging mobile
CCT were consistently further from spawning habitats used by stationary CCT in each group.
Spawning Migrations
Radio tagged CCT moved into spawning tributaries from March 28 to May 6 in year 1
(median = April 19; n = 25) and from April 11 to May 9 in year 2 (median = May 1; n = 22).
When sex and behaviour data were combined, CCT arrived in spawning tributaries
significantly earlier in year 1 than year 2 (Table A1.22). Between year differences were also
apparent among staging CCT when sex and behaviour data were combined (Figure 1.18A
and Figure 1.19A), but not among non-staging CCT (Figure 1.18B and Figure 1.19B).
The timing that CCT moved into spawning tributaries differed between years, but
not between sexes, behavioural groups or staging and non-staging fish. Male and female
CCT entered spawning tributaries at similar times and comparisons of sex data did not
identify any significant differences (Table A1.22; Figure 1.18A and B). However, male CCT in
51

year 2 arrived later, but not significantly later than males in year 1 when staging and nonstaging CCT were combined and when staging CCT were assessed independently. Stationary
CCT consistently moved into spawning tributaries earlier than mobile CCT, but no other
trends were apparent in the comparisons of behavioural groups (Table A1.23; Figure 1.19).
Spawning is assumed to have occurred at the maximum upstream relocation
position within putative spawning tributaries. Radio tagged CCT spawned 0 to 24 days after
first arriving in spawning tributaries (mean = 5.2 ± 0.5 days). Spawning occurred significantly
earlier in year 1 (from April 6 to May 17; n = 23) than in year 2 (April 17 to May 15; n = 21).
In year 2, staging CCT spawned significantly later than non-staging CCT and later than
staging CCT in year 1 (Table A1.24).
During each year, male and female CCT spawned at similar times. In year 1, males
spawned significantly earlier than in year 2, but this difference was not identified among
females (Table A1.24). Nor were statistically significant differences apparent between male
and female CCT during either year. Mobile CCT spawned later than stationary CCT in each
year, but the difference in timing was not statistically significantly (Table A1.25).
Comparisons between years also failed to identify significant differences in the date that
mobile and stationary CCT spawned. Similarly, spawn date did not differ statistically
between staging and non-staging CCT.

52

A

B

Figure 1.18. Median date that staging (A) and non-staging (B) male and female CCT arrived in spawning
tributaries in year 1 and year 2

A

B

Figure 1.19. Median date that staging (A) and non-staging (B) mobile and stationary CCT arrived in spawning
tributaries in year 1 and year 2.

53

Distribution of Spawning Habitats
Spawning activity was observed within the lower (0 to 21 rkm; 57% of all spawning
activity), middle (21 to 41 rkm; 32%) and upper (>41 rkm, 11%) reaches of the Kitimat
watershed (Figure 1.20, Table A1.26). The majority of spawning activity (n = 34, 72%) was
observed within 9 of the 13 major drainages identified by Macdonald & Shepherd (1983).
The remaining 28% (n = 13) of spawning activity occurred within 7 minor 1st to 4th order
streams draining directly into the Kitimat River.
Within major drainages, putative spawning positions were observed in the main
channel (n = 16), as well as within secondary and tertiary streams to the main channel (n =
18) (Figure 1.20, Table 1.5). First (22%), second (61%) and third (17%) order streams were
used by CCT that spawned in secondary and tertiary tributaries. Spawning CCT were
relocated as far as 30.9 km from the mainstem of the Kitimat River in major tributaries
(mean = 7.0 ± 1.1 km) and 6.9 km in minor tributaries (mean = 3.8 ± 0.5 km). Cutthroat
travelled up to 23.3 km to access secondary tributaries within major drainages (mean = 5.1
± 1.3 km) and then travelled up to an additional 3.5 km within secondary and tertiary
tributaries to reach putative spawning areas (mean = 1.3 ± 0.3 km). Three cutthroat
spawned within the lower 1.2 ± 0.2 km of first and second order streams draining directly
into the mainstem of the Kitimat River. These spawning streams were primarily within the
upper watershed and joined the Kitimat River between 31 rkm and 68 rkm.

54

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Major Tributaries
n % of All Spawners

Minor Tributaries
n % of All Spawners

n

Combined
% of All Spawners

Lower Watershed
Middle Watershed
Upper Watershed

7
23
4

15%
49%
9%

8
4
1

17%
9%
2%

15
27
5

32%
57%
11%

Total

34

72%

13

28%

47

100%

!

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Spawning Mortality
Greater than half of all radio tagged CCT did not survive spawning in year 1 (56%)
and year 2 (59%). No differences in mortality rate were observed between main channel
and secondary/tertiary spawning CCT (Table 1.6). Nor were statistical differences detected
between years, winter behavioural groups, sexes and staging and non-staging CCT.
Mortality was greatest among male, mobile and staging CCT than among female, stationary
CCT and non-staging CCT, respectively, however statistical differences between groups were
non-significant.
Post Spawning Behaviours
Following spawning, surviving CCT travelled directly towards the estuary or travelled
to positions in the mainstem or major tributaries. Less than half (9) of the 20 surviving CCT
travelled directly towards the Kitimat River estuary following spawning. These CCT moved
out of the Kitimat River (past the lowermost receiver stations) from May 20 to June 3 of
year 1 and from June 1 to June 3 of year 2. Diadromous CCT spent a mean of 51.3 ± 8.9 days
in the estuary and returned to Kitimat River from July 1 to September 6 in Year 1 (median =
July 23) and from June 28 to July 18 of year 2 (median = July 5). Following spawning, 11 CCT
moved to habitats in the mainstem (n = 8) and lower reaches of major tributaries (n =3).

56

Table 1.6. Summary of the relative mortality of CCT spawning within the main channel, and secondary and tertiary streams of major and minor tributaries to
the Kitimat River.

Spawning Water Body

All CCT
Main Channel Spawning CCT
2° and 3° Spawning CCT
# Spawned # Survived % Mortality # Spawned # Survived % Mortality # Spawned # Survived % Mortality

Hirsch Creek
Big Wedeene
Little Wedeene
Nalbeelah Creek
Humphrey Creek
Deception Creek
Cecil Creek
Chist Creek
McKay Creek

5
8
2
4
1
2
8
2
2

2
4
1
1
1
0
4
1
2

60%
50%
50%
75%
0%
100%
50%
50%
0%

0
2
0
4
1
2
5
1
1

1
1
1
0
4
1
1

50%
75%
0%
100%
20%
0%
0%

5
6
2
0
0
0
3
1
1

2
3
1
0
0
1

60%
50%
50%
100%
100%
0%

All Major Tributaries

34

16

53%

16

9

44%

18

7

61%

Duck Creek
Goose Creek
McNeil Creek
Powerline Creek
Unnamed Creeks*

3
3
2
2
3

1
1
1
0
1

67%
67%
50%
100%
67%

3
2
2
2
3

1
1
1
0
1

67%
50%
50%
100%
67%

0
1
0
0
0

0
-

100%
-

All Minor Tributaries

13

4

69%

12

4.0

66.7%

1

0

100%

57

DISCUSSION

Radio tagged CCT in the Kitimat River displayed fluvial and diadromous life history
strategies. Fluvial CCT moved between the mainstem and tributaries of the Kitimat River.
Diadromous CCT moved throughout the mainstem and tributaries but also travelled into the
estuary following spawning. High mortality throughout the spawning period limited the
extent to which CCT could be defined as diadromous or fluvial. Furthermore, radio tagged
CCT were not tracked for the duration of their life and it is possible that CCT displaying
fluvial behaviours throughout the study period had previously, or would later, move into
marine environments. Thus, described behaviours are considered for migratory CCT, which
includes both diadromous and fluvial life history strategies. The results of this study should
not be extended to stream resident CCT as they were not sampled during this research.
The behaviours displayed by radio tagged CCT fit within Northcote’s (1997a)
functional model of migration and residency. In the fall, CCT moved into habitats that
provided refuge through the winter and in the spring, they moved from refuge to
reproductive and then foraging habitats. However, when considered at a finer resolution
the overwintering and spawning movements of radio tagged CCT appear to be more
complex than have been previously documented for the subspecies. Indeed, multiple
overwintering behaviours as well as pre-spawn staging behaviours were observed.
For many salmonids, winter is believed to be a period of reduced survival (Huusko et
al. 2007). To improve winter survival, CCT select habitats that promote energy conservation
and provide refuge from deleterious environmental conditions (Northcote 1997b, Harvey et
al. 1999, Huusko et al. 2007, Trotter 2008). In this study, radio tagged CCT aggregated in
58

deep, slow moving pools within side-channels and sloughs of the mainstem of the Kitimat
River. The character and structure of these habitats are similar to the deep pool habitats
used by more southern CCT populations (Bustard and Narver 1975a, Harvey et al. 1999,
Slaney and Roberts 2008) and to the beaver ponds that are used in Alaska’s Copper River
Delta (Saiget et al. 2007). The use of off-channel habitats in this study suggests that the
subspecies will select habitats that are best able to provide refuge throughout the winter –
demonstrating the subspecies’ ability to adapt to conditions of the local environment.
My study also showed that deep, slow moving off-channel habitats provide critical
winter refuge for CCT in the Kitimat watershed. The importance of these habitats was
reinforced by the fact that all major overwintering aggregations shared similar physical
characteristics and that they were used during both years of the study. Furthermore, CCT
appeared to actively select deep, slow moving off-channel habitats. Indeed, relative to
other habitat types in the watershed, habitats matching the characteristics of the major
overwintering aggregations were relatively limited in number, yet all habitats with these
characteristics were used extensively. Additionally, mobile CCT consistently moved between
aggregations and were infrequently relocated outside of them, suggesting that they were
moving to specific habitats.
Recreational anglers frequently targeted aggregated CCT throughout the winter. For
a number of reasons, this should be of concern to regional fisheries managers. First, if the
behaviours of radio tagged CCT are representative of the greater population of CCT in the
Kitimat watershed it is reasonable to assume that the majority of CCT are concentrated
within a limited number of habitats during the winter. Thus, targeting aggregated CCT may
59

promote a false sense of abundance among anglers, which may contribute to illegal
retention (personal observation). In addition, capture by angling is physiologically stressful
and energetically taxing (Ferguson and Tufts 1993, Meka and Margraf 2007). Thus, angling
aggregated CCT may diminish the ability of overwintering habitats to provide winter refuge.
Given that winter can be a period of increased mortality and that habitat selection appears
to be a survival strategy, angling overwintering CCT could have long term detrimental
population affects. Measures that provide additional protection of overwintering habitats
should, therefore, be considered if there is concern about the status of CCT populations in
the region.
Previous studies of CCT have generally stated that CCT remain within a single
overwintering habitat throughout the winter (Trotter et al. 1993, Saiget et al. 2007, Trotter
2008). My findings, however, demonstrate that CCT may remain stationary within a single
habitat, or move between multiple habitats throughout the winter. To the best of my
knowledge, winter movement of lotic CCT at the scale and frequency reported in this study
has not been described previously. Among other subspecies of cutthroat trout, winter
movement appears to be common. Indeed, WCT appear to move frequently throughout the
winter and similar mobile and stationary behaviours have been reported for the subspecies
(Brown 1994, 1999, Jakober et al. 1998, Morris and Prince 2004). Given these observations
and the frequency that radio tagged CCT moved between habitats, it is possible that
cutthroat, as a species, may be more mobile throughout the winter than has been
previously considered. Furthermore, similar behavioural structuring has been observed in

60

studies examining the marine habitat use of CCT (Krentz 2007, Goetz et al. 2013), suggesting
that CCT may adopt specific behavioural strategies throughout key life stages.
The factors contributing to the distinct winter behaviours observed in this study are
not clear. However, studies of other salmonids provide insight and suggest that winter
movements may be due to changes in environmental conditions, interspecific competition
and/or external stressors (Mäki-Petäys et al. 2004, Huusko et al. 2007, 2013, Meka and
Margraf 2007). Additional clarity is likely to be provided by studies that employ
biotelemetry and monitor winter movements of migratory CCT in multiple watershed and at
a finer temporal resolution.
Changes in water temperature and habitat occlusion caused by instream ice
formation are frequently cited as a source of winter movement (Brown et al. 1993, Brown
and Mackay 1995b, Jakober et al. 1998, Morris and Prince 2004, Huusko et al. 2013).
Periods of hypercooling and instream ice formation were observed during both years of this
study. The influence of water temperature and ice formation on winter movements,
however, could not be assessed due to the low temporal resolution of the winter tracking
data. It is likely that temperature, flow and ice conditions did contribute to the observed
winter movements, but it is unlikely that they were the sole factor promoting winter
movement. Indeed, movement was observed throughout the winter and not strictly during
hypercooling or high flow events. Furthermore, radio tagged CCT remained within
overwintering habitats throughout the winter and no single ice or flow event resulted in the
movement of all individuals from a habitat.

61

In this study, stationary CCT were significantly older, longer and heavier than
stationary CCT, suggesting that movement between overwintering habitats may be in
response to interspecific competition. Dominance hierarchies and interspecific cohort
segregation are often observed during studies of salmonids, and may be more pronounced
in winter if multiple cohorts aggregate in the same habitats (Mäki-Petäys et al. 2004,
Huusko et al. 2007). Furthermore, interspecific competition for habitats may increase when
refuge habitats are of limited availability, which may benefit larger individuals (Harwood et
al. 2001, Huusko et al. 2007). Intraspecific competition is less likely to have influenced
winter behaviours as the two other salmonid species present in the watershed during the
winter, Dolly Varden and resident rainbow trout, were consistently smaller than CCT
selected for radio tagging.
Recreational anglers were frequently observed targeting overwintering aggregations
and stress associated with catch-and-release angling may have promoted movement
between overwintering habitats. Certainly, capture by angling is a physiologically stressful
and energetically taxing event and it is possible that movements out of overwintering
habitats were an avoidance response (Ferguson and Tufts 1992, Meka and Margraf 2007).
Arguably, activities that increase stress and energy expenditure while reducing foraging
potential diminish the capacity of overwintering habitats to function as refuges. Future
studies employing biotelemetry are recommended to better understand the extent to
which catch and release angling affects the winter movements of CCT (Donaldson et al.
2008).

62

Pre-spawn staging behaviours have been well documented among salmonids (e.g.
Colyer et al. 2005, High et al. 2011, Starcevich et al. 2012). Spawning movements of CCT,
however, have generally been described as direct from overwintering to spawning habitats.
To the best of my knowledge, pre-spawn staging behaviours of CCT have not been
thoroughly assessed, though indirect references in recent studies suggest the behaviour
may be more common than has been recognized. For instance, Saiget et al. (2007)
described 4 CCT that held in small pools for 3-14 days while travelling towards spawning
habitats. Temporary staging prior to spawning may be advantageous if it permits individuals
to assess natal stream conditions, or select mates.
In my study, CCT were observed moving from overwintering to staging habitats prior
to spawning. Staging habitats were 0.1 to 36.2 km from overwintering habitats and 0.8 to
14.0 km from spawning habitats. Cutthroat arrived in staging habitats from late March to
early May and departed after a period of 1 to 25 d. Interestingly, stationary CCT were often
observed in overwintering locations that were proximal to spawning tributaries (i.e. 0.1 km
from confluence with spawning tributary). Radio tagged CCT staged in multiple locations
including at the confluence of small first to 3rd order tributaries flowing into the mainstem
and major tributaries; at the confluence of major tributaries with the Kitimat River and in
the Kitimat River mainstem itself. Searching behaviours were common and involved
movement into the lower reaches of a stream before returning to the staging location.
From staging habitats CCT moved directly to putative spawning positions.
Radio tagged CCT were not observed actively spawning, nor were redds of radio
tagged CCT identified during bank walks of spawning tributaries. However, observations of
63

non-radio tagged CCT spawning as well as radio tagged CCT paired with migratory and
stream resident CCT within first to third order streams suggests that movements into small
tributaries in the spring were to spawn. Radio tagged CCT were first relocated in spawning
tributaries from the last week of March to the first week of May, with peak arrival occurring
in late April. Arrival at putative spawning positions occurred slightly later, from the first
week of April to mid-May, with peak spawning occurring in late April and early May. Spawn
times reported in this study are consistent with records of spawn timing throughout the
range of CCT (Jones and Harding 1998, Jones and Yanusz 1998, Slaney and Roberts 2005,
Saiget et al. 2007, Trotter 2008, Moore et al. 2010, Buehrens 2011, Marston et al. 2011,
Stein et al. 2012b).
Coastal cutthroat may spawn in the upper reaches of small tributaries where other
salmonids are less abundant to reduce competition of juvenile CCT with coho salmon and
steelhead (Pearcy et al. 1990) and/or reduce hybridization with steelhead (Buehrens et al.
2013). In this study, radio tagged CCT were observed within ephemeral streams and in the
upper most accessible reaches of small first to third order streams. Generally, tributaries
used by radio tagged CCT throughout the spawning period were of similar character to
those that have been previously described for the subspecies (e.g. Roberts and Slaney 2005,
Costello 2006, Trotter 2008).
Mortality of spawning radio tagged CCT was high and demonstrates the risks that
migratory CCT incur while spawning in relatively small streams. Similar rates of mortality
have been observed in studies of CCT (Costello 2006) and WCT (Schmetterling 2011). When
transmitters were recovered from dead radio tagged CCT, it was not clear what was the
64

cause of death. A number of factors are likely to have contributed to the high rates of
observed spawning mortality including, but not limited to: predation by eagles and otters;
tagging related complications; intraspecific competition; fatigue from spawning, and;
unfavorable environmental conditions. The extent to which each of these factors
contributed to observed mortality rates is unclear; however, evidence of predation by
eagles and otters was observed during bank walks of spawning tributaries.
Radio telemetry has the capability to provide great insight into the behaviours of
cryptic species. However, the technology is not without its limitations, and biases in
sampling design can influence how behaviours are interpreted (Adams et al. 2012).
Variability in the frequency with which individuals are relocated can result in contact bias
(Jones and Rogers 1998, Rogers and White 2001, Adams et al. 2012). In this study, the
frequency of ground and aerial based relocation events as well as the behaviours of CCT
(which influenced relocation success) contributed to contact biases. Indeed, the increased
duration between relocation events throughout the winter is likely to have underestimated
movement. Similarly, individuals that remained within known habitats were relocated more
often than individuals that moved into new habitats. Thus, relocation success was greatest
throughout the winter and lowest throughout the spring spawning period.
In addition to biases resulting from the application of radio telemetry, additional
forms of bias may have been introduced by the location, timing and methods of sampling.
Recent evidence suggests that resident and migratory life history forms are part of a single
randomly mating population (Johnson et al. 2010). Given that sexual selection is likely to
favour migration among females (Jonsson and Jonsson 1993) it is possible that targeting
65

large, mobile CCT during sampling may have influenced sex ratios in this study. If CCT in the
Kitimat watershed are panmictic (Johnson et al. 2010), it is therefore possible that a more
balanced sex ratio would have been observed if resident CCT were included in sampling
(Downs et al. 1997, Meyer et al. 2003). Similar sex ratios have been documented in studies
of sea-run and lacustrine CCT populations where resident CCT were not sampled (Sumner
1972, de Leeuw 1987, Johnson et al. 1994, Foster 2003, Costello and Rubidge 2005).
Consequently, the female biased sex ratios reported here are not likely to be representative
of the Kitimat River CCT population as they fail to include stream resident CCT.
Sampling was conducted significantly later in year 1 than year 2, and radio tagged
CCT were significantly larger in year 1 than year 2. However, a Spearman correlation test of
capture date and fish length, weight, age and condition factor failed to detect a significant
relationship between physical characteristics and capture date (results not presented). It is
thus unlikely that the difference in the timing of sampling in year 1 and year 2 affected the
observed behaviours.
The observations that I have reported on in this chapter demonstrate that there is
considerable variability in the behaviours of individual CCT and that this variability often
limits the statistical differentiation of relationships that may be of biological significance.
Distinct behavioural patterns, however, were apparent when the data was considered at a
coarser scale which focused on seasonal movement patterns. Indeed, this approach
demonstrated that CCT displayed one of two behaviours throughout the winter.
Additionally, movements from overwintering to spawning habitats and movements from
spawning habitats to the estuary were highly synchronized and coordinated in each year.
66

Thus, my study suggests that CCT often behave in unison and that the subspecies’ may be
no more individual than any other species of salmonid.
In chapter 2, I apply a logistic regression modeling approach to explore the extent to
which the timing that CCT moved from overwintering habitats to spawning habitats was
influenced by a suite of biotic and abiotic conditions. The timing that these migrations were
completed differed significantly between years and there is considerable evidence
suggesting that salmonids are capable of adjusting migration behaviours in response to
environmental conditions (see reviews by Jonsson 1991, Jonsson and Jonsson 2009, Taylor
and Cooke 2012, Milner et al. 2012). Little is known, however, about the behavioural
responses of CCT to changes in their environment. Fortunately, telemetry studies are
particularly well suited to assess how behaviours are influenced by the environment (e.g.
Erkinaro et al. 1999, Bendall et al. 2012, Thorstad et al. 2013), especially when considering
migrations during ecologically sensitive periods, such as spawning (Tetzlaff et al. 2005). In
combination, these two chapters provide insight into the seasonal behaviours of CCT and
the factors that affect them.

67

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Photoperiod is an anticipatory cue for important life history events in a range of
aquatic, avian and terrestrial species (Bradshaw and Holzapfel 2007). Among salmonids,
photoperiod is believed to have both ultimate and proximate effects on migratory
behaviour by synchronizing seasonal migrations and initiating physiological processes that
may motivate migration, respectively (Thorstad et al. 2005, Binder et al. 2011). Photoperiod
has been shown to initiate and influence the maturation cycle of rainbow trout
(Oncorhynchus mykiss; Duston and Bromage 1986, Carrillo et al. 1989) and Atlantic salmon
(Salmo salar; Duston and Saunders 1990, Björnsson et al. 1994) and is considered to be the
dominant environmental cue stimulating physiological changes associated with smolting in
anadromous forms of both species (Zaugg and Wagner 1973, McCormick et al. 2002 and
references within). Less understood is how physiological changes influence an individual’s
internal motivations to move (Thorstad et al. 2005, 2008) which may be affected by energy
and stress levels, maturation state and hormones (Milner et al. 2012). Maturation,
therefore, might motivate movements towards spawning habitats as gravid females have a
relatively short window within which eggs are viable (Thorstad et al. 2008, Quinn 2011).
Stimulating physiological changes that are likely to affect internal motivations, photoperiod
may function to ensure that behaviours occur during temporal periods that have been
determined through selection. Day length has also been shown to ultimately affect
migration behaviours by directly stimulating rheotaxis (Dodson and Young 1977, Martin et
al. 2012). The fact that the timing of life history events differs considerably between
individuals within a population, however, reinforces that photoperiod is not the only factor
influencing when behaviours are undertaken.
69

There is considerable evidence that migrations are influenced by prevailing stream
conditions in larger bodied salmonids such as Atlantic salmon (see reviews by Jonsson 1991,
Tetzlaff et al. 2005, Taylor and Cooke 2012, Milner et al. 2012). Similar results have been
reported in studies of smaller salmonids such as brown trout (S. trutta), rainbow trout (O.
mykiss), bull trout (Salvelinus confluentus) and multiple subspecies of cutthroat trout (O.
clarkii) (Waters 1993a, Brown and Mackay 1995a, Swanberg 1997, Jakober et al. 1998,
Simpkins et al. 2000, Meka et al. 2003, Stephan and Zurstadt 2004, Svendsen et al. 2004,
Harper and Farag 2004, Bahr and Shrimpton 2004, Friesen 2005, Colyer et al. 2005, Bryant
et al. 2009, Young et al. 2010, Gregory et al. 2011, Starcevich et al. 2012, Bennett et al.
2014, Ringel et al. 2014), suggesting that trends observed in Atlantic salmon are applicable
to other salmonids. Discharge and water temperature are primarily identified as the
environmental variables affecting migrations (Table A2.1 and A2.2). Although considerable
variation has been reported among species and populations in their response to
environmental variables, such differences likely indicate that populations have adapted
responses to meet conditions of the local stream environment (Thorstad et al. 2008,
Bronmark et al. 2013). The high incidence of homing as well as evidence of diminished
reproductive success among straying salmonids is certainly indicative of local adaptation at
the population scale (Dittman and Quinn 1996).
Temperature influences the rate at which physiological processes, such as
maturation occur (Hoar et al. 1983, McCormick et al. 2002, Wilkinson et al. 2010), but also
influences migration capacity (Brett 1971, Quinn 2005). Physiological processes function
optimally within a relatively narrow thermal range (Farrell 2002, Lee et al. 2003).
70

Movements will likely occur at temperatures that maximize physiological efficiency and
function to conserve energy for critical life history processes such as spawning. In contrast,
sexual maturation which occurs over a period of months is also affected by temperature
and is dependent on an individual’s thermal experience, which is typically measured in
accumulated thermal units (ATUs) (Petty et al. 2012, Chezik et al. 2014). Field and
laboratory studies of the effects of antecedent water temperatures have shown that
increased water temperatures can stimulate early sexual maturation (Quinn and Adams
1996, Sauter et al. 2001, Dahl et al. 2004, Clark et al. 2005, McMillan et al. 2011). The effect
of temperature on spawning migrations, however is equivocal. Indeed, spawning migrations
of coastal cutthroat trout (CCT) have often been positively associated with water
temperature, but not always (Webb and McLay 1996, Gresswell et al. 1997, Jones and
Harding 1998, Stephan and Zurstadt 2004, DeRito et al. 2010, Bennett et al. 2014). Similar
inconsistencies have been observed in other species of salmonids and suggest local
adaptation (Table A.1).
Responses to flow are variable among species and populations, however several
patterns have been reported in the literature. First, flow response is relative to river size
(Thorstad et al. 2008, Milner et al. 2012). Fish moving through large rivers are less likely to
be affected by flow than those moving through small streams where reduced flows may
physically limit habitat connectivity (Milner et al. 2012). Second, response to flow may vary
based upon migration stage (Thorstad et al. 2008). Individuals may show minimal response
to flow, therefore, while still moving through large rivers towards natal streams, but may
delay entry into natal streams until flows are sufficient to enable movement past instream
71

obstacles. Third, salmonids are most likely to respond to flow during specific life history
stages or transitions, when internal motivations are elevated. For instance, migratory
individuals can be expected to show a stronger response to flows than fish that are foraging
or rearing. Finally, variability in the timing of life history events between years is common
and may be related to interannual variability in temperature and flow regimes, as well as
past climatic conditions (Smith et al. 1994, Gresswell et al. 1997, Dahl et al. 2004, Tetzlaff et
al. 2005, Budy et al. 2012, Milner et al. 2012, Bennett et al. 2014).
The migrations of CCT from overwintering habitats to spawn were described in
Chapter 1. As coordinated movements, departures from overwintering habitats represent
the initiation of the spawning migration which are then culminated upon arrival within
spawning tributaries (or more accurately at the arrival to spawning locations). However, it is
likely that CCT will key in on different environmental stimuli during each stage of the
migration. For instance, the distance that CCT travelled to reach spawning tributaries was
frequently much greater than the distance travelled within spawning tributaries. Given
metabolic costs of migration are increased when water temperatures are above or below a
species thermal optima, it seems plausible that movements out of overwintering habitats
would not occur until a threshold temperature had been achieved. Further, fish may show
an elevated response to flow while moving into and within spawning tributaries relative to
when they are moving towards them. Indeed, overwintering habitats were primarily within
the mainstem of the Kitimat River and low flows are unlikely to have limited movements
out of overwintering habitats. Whereas elevated flows will increase access to the upper
reaches of small spawning tributaries, reduce predation and contribute to olfaction.
72

In addition to water temperature and discharge, several biotic factors are also likely
to influence migratory behaviours. Previous research has observed variation in migratory
behaviours between fish of different sex, size and life history type. For instance, Yanusz
(1997) found that larger, predominantly female CCT in SE Alaska initiated movements from
overwintering to spawning habitats earlier. Similar size gradients have also been observed
in studies examining the spawning behaviours of steelhead, bull trout, brook trout (S.
fontinalis) and Atlantic salmon (Swanberg 1997, Curry et al. 2002, Dahl et al. 2004, McLean
et al. 2005). The factors contributing to size segregation, however, are not well understood.
Differences in migration behaviour between male and female salmonids are also
well described (Dahl et al. 2004). For instance, female CCT may favor migration as increased
size correlates positively with fecundity, in terms of eggs size and number (Downs et al.
1997). Differences in reproductive capacity may also influence the spawning behaviours of
males and females. Females have a finite number of eggs and a relatively short temporal
window to complete oviposition and are likely to move out of spawning habitats once
oviposition is completed (Hoar et al. 1983). In contrast, males are capable of producing
sperm throughout the spawning period and their reproductive capacity is only limited by
the availability of females and the amount of energy that can be invested in
spermatogenesis. Males may therefore maximize reproductive success by moving into
spawning tributaries with the earliest mature females, and/or remaining within spawning
tributaries for the duration that ripe females are present and available.
The distance separating habitats will also influence the timing that migrations are
initiated and/or completed. Certainly, individuals travelling greater distances between
73

habitats should be expected to initiate migrations earlier, or complete them later. For
instance Bahr and Shrimpton (2004) observed that bull trout travelling the furthest distance
to spawn were the earliest to initiate migrations. The distance that CCT travel to access
spawning habitats may also differ among life history types and may influence how
individuals respond to environmental cues. For instance, Quinn and Adams (1996)
suggested that endogenous rhythms will have the greatest influence on the spawning
migrations of species that complete long distance migrations and do not directly experience
the environmental conditions of natal streams throughout much of their life, such as
sockeye salmon (O. nerka). In contrast to sockeye salmon, the authors argue that spawn
timing will be more variable among species that remain proximal to natal tributaries or
within a single watershed (E.g., American shad, Alosa sapidissima) as these species are
more likely to be influenced by, and respond to variable environmental cues stimuli. Their
finding was corroborated by Dahl et al. (2004) who demonstrated that interannual
variability in spawn timing was greater among brown trout than among further ranging
Atlantic salmon. Relative to other species of Pacific salmon and trout, CCT are not far
ranging and it is therefore possible that the subspecies will show an elevated response to
environmental stimuli during migrations.
The life history behaviours and population structure of CCT make them particularly
well suited for the study of migration behaviours at the watershed scale. Evidence of stream
level population structure and diminished reproductive success among mature strays
suggest that CCT are highly adapted to their local environment (Wenburg and Bentzen
2001, Quinn 2005). Furthermore, CCT generally remain in fresh water and are relatively
74

sedentary throughout the winter prior to spawning in the spring. Due to the relatively
sedentary nature of their overwintering behaviours, CCT can be tracked from overwintering
to spawning habitats with relatively high temporal and spatial precision using radio
telemetry. When combined with measures of the environment and the physical
characteristics of radio tagged CCT, the telemetry data can provide invaluable insight into
the factors that are structuring the migratory behaviours of CCT. Chapter 1 presented
evidence of at least two coordinated spring movements: movement from overwintering
habitats and migration to spawning habitats. In this chapter I will apply an information
theoretic approach to examine how a set of biological and abiotic factors may have
influenced these two behaviours.

METHODS

Fish Sampling and Tracking
Methods employed to sample, radio tag and relocate radio tagged CCT are described
in Chapter 1.

Environmental Data Collection
Water temperature was monitored throughout the Kitimat watershed using HOBO
Data Loggers (Onset Computer Corporation). HOBO loggers were encapsulated within a
perforated ABS pipe attached to a concrete cinder block that was submerged and anchored
to shore. Each recorder measured water temperature on 4 hour intervals. A total of
75

nineteen temperature loggers were distributed throughout the watershed: four throughout
the mainstem of the Kitimat River; nine in major tributaries, and; six in minor tributaries
(Figure 2.1). Eight HOBO loggers were deployed into suspected spawning tributaries in 2012
and an additional 8 were deployed into confirmed tributaries in 2013. To assess how
mainstem water temperature varied throughout the study area, temperature loggers were
deployed at 11.2 rkm and 38.3 rkm in 2012. In 2013, additional mainstem loggers were
deployed at a key overwintering area (30.4 rkm) as well as within the upper watershed at
48.3 rkm. However, the logger at 48.3 rkm was displaced by ice, resulting in unreliable
temperature metrics and has not been included. Tributary water temperatures are
summarized in Table A2.3, but tributary temperatures were not included in either analyses
as temperature was not recorded in all spawning tributaries nor was it available for both
years of the study. Mean daily mainstem water temperatures (collected at 11.2 rkm) were
summed for the period from November 15 of each year to calculate the thermal experience,
or accumulated thermal units (ATU) in each year. Thermal experience was calculated from
November 15 as it was roughly the date when water temperatures first approached 0 °C in
each year.
Discharge data was collected by Environment Canada and downloaded from the
website of the Water Survey of Canada (https://wateroffice.ec.gc.ca/). Environment Canada
operates three stations within the Kitimat watershed, however, data was only collected
from the station that operated on the Kitimat River, downstream of Hirsch Creek (Station
08FF001). Hydrometric data was collected continuously at a 5-minute interval and are
reported as mean daily values.
76

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Statistical Analyses
Welch’s two sample t-test was used to compare measures of mean daily water
temperature and discharge between years. Discharge and water temperature were tested
for the tracking period (October to June) as well as for the period when CCT were observed
moving out of overwintering habitats and into spawning habitats (March to June). Analysis
of variance (ANOVA) was applied when more than two groups were compared and was
used to test for differences in mainstem flow between years and for differences in
temperature between mainstem logger sites and years. Tukey’s test was used to compare
means when significant differences were identified. Variance in temperature was assessed
for normality and homogeneity using Bartlett’s and Levene’s tests prior to analyses. For all
tests, alpha values less than 0.05 were deemed significant. Summary values for all measures
are presented as mean ± SD.
Modelling
An information theoretic approach (Burnham and Anderson 2002) was applied to
assess how a suite of biotic and abiotic metrics influenced two observed life history
behaviours: movement out of overwintering habitats, and; movement into spawning
habitats. Candidate models were developed using parameters identified from previous
research and were ranked using Akaike’s Information Criterion (AIC). The factors influencing
the life history behaviours of CCT are understudied consequently research was expanded to
include other cold water salmonids with similar life history behaviours. Species reviewed
include westslope cutthroat trout (WCT; O. clarkii lewisi), Brook trout, Brown trout,
Rainbow trout / Steelhead, Bull trout, and Atlantic salmon. This review identified four
78

abiotic (photoperiod, discharge, water temperature, and thermal experience) and three
biotic parameters (fork length, sex, and distance from overwintering to spawning habitats)
that have been shown to influence life history behaviours. An additional biotic metric,
migration type, was included to distinguish between CCT displaying mobile and stationary
behaviours during each winter. Due to limitations in sample size, year was not
differentiated within candidate models.
Mobile and stationary relocation data was used to identify the median date that
behaviours were completed by each CCT. Median departure dates from overwintering
habitats were calculated as the median date between the final relocation within
overwintering habitats and the first observation outside of overwintering habitats. Similarly,
the date of spawning tributary arrival was calculated as the median date between the last
observation outside of, and the first relocation within a spawning tributary. To account for
variability in the frequency that each CCT was relocated, date was broken into 27, 4-day
temporal periods from February 15 to June 1 of each year. A binary metric was then
calculated to identify whether each CCT did (1), or did not (0) complete movements within a
given temporal period. For each CCT, a minimum of 4 consecutive periods were included in
the analysis and once a behaviour was observed no further periods were included. Mean
values of the abiotic variables were calculated for each temporal period. Measures of water
temperature and discharge were calculated using data collected in the mainstem of the
Kitimat River. Sex and migration type were included as categorical variables. Distance to
spawn was calculated as the total absolute distance CCT travelled from final overwintering
habitats to maximum upstream spawning positions. Separate longitudinal datasets
79

comprised of repeated measures of each CCT were prepared for the overwintering and
spawning analyses.
In each candidate model, biotic and abiotic measures were treated as predictor
variables and event (indicating either overwinter departure, or spawning arrival) was
treated as the response variable. Candidate models were assessed by standard logistic
regression, however standard errors were clustered by individual fish. Models were
evaluated by examining coefficient estimates, standard errors and confidence intervals.
Multicollinearity was assessed by visually inspecting Spearman correlations between
metrics and by calculating variance inflation factors and tolerance values for each variable.
Logistic regressions were performed in STATA (StataCorp 2015), two-sample t-tests,
ANOVA’s and Tukey’s tests were performed using R (R Core Team 2016). All figures were
prepared using the ggplot2 package in R (Wickham 2009).
Overwintering departure and spawning arrival models were assessed on
independent data sets. Models in each candidate set were ranked by AIC, corrected for
small sample size (AICc) (Burnham and Anderson 2002, Symonds and Moussalli 2011).
Models with the lowest AICc value were deemed to be the best fit of the data. Competing
models with AICc values < 2 were considered to be as good as the top model. The receiver
operating characteristic (ROC) curve, relates the relative proportions of correctly and
incorrectly classified predictions. The area under the ROC curve is an index of model
performance and was calculated to assess the predictive ability of each model (Hanley and
McNeil 1982).

80

RESULTS

Summary of Abiotic Conditions
Overwintering and spawning migrations occurred when photoperiod was increasing
in the spring (Figure 2.2). Mainstem water temperatures declined rapidly in the late fall,
remained cool through the winter and warmed again in the spring (Figure 2.3).
Temperatures did not differ significantly among mainstem logger sites during either year;
nor was a difference apparent between years when mainstem temperature was compared
from October to June. Mean temperatures recorded in tributaries ranged from 1.6 to 5.4 °C
during the winter and 2.9 to 5.8 °C throughout the spawning period (Table A2.3). The
number of CCT observed in temperature monitored tributaries and the temperatures during
their use are presented in Table A2.4. Tributary temperatures were not included in any
additional analyses. Extended periods of sub-zero air temperatures were associated with
extensive ice formation throughout the Kitimat watershed and resulted in mean daily water
temperatures below 0 °C (Figure 2.3). The timing of ice events differed between years.
Major ice events occurred from December 22 to 30 and January 10 to 14 in year 1 and from
December 6 to 9 and February 1 to 13 in year 2. Subsurface and frazil ice were observed
during the longer ice events in each year.
Historic mean ± SD annual discharge in the Kitimat River is 132 ± 116 m3/s,
calculated from 1965 to 2012 and show that peak flows primarily occur with the spring
freshet (Figure 2.4). The Kitimat River typically remains low and clear throughout the
winter, although short duration high flow events frequently occur following rain on snow
events (Figure 2.4). Flows in year 1 did not differ from historic flows, however flows in year
81

2 were significantly greater than flows in year 1 and historic flows (Table 2.2). The increased
variability in flows recorded during year 2 was likely due to differences in snow pack
between years. Indeed, snow levels in year 1 were minimal compared to year 2 (personal
observation).

Figure 2.2. Trends in daily measures of day length recorded in Kitimat BC, from October 1 to June 1.

Table 2.1. Summary of grand mean and minimum water temperatures recorded at mainstem temperature
logging sites in year 1 and year 2 from November 1 to May 31.

Year

rkm

1
1

11.2
38.3

Mean

Mean
SD

Range

2.98
2.89

2.19
2.07

0.0 - 8.0
0.0 - 7.9

t(420.6) = 0.44, p = 0.66
2
2
2

11.2
30.4
38.3

2.81
2.8
2.72

2.13
2.40
2.13

0.0 - 8.3
0.0 - 8.2
0.0 - 7.7

F[2, 633] = 0.95, p = 0.91

Mean

Minimum
SD

Range

2.33
2.22

1.76
1.65

0.0 - 6.3
0.0 - 6.0

t(420.4) = 0.70, p = 0.49
2.28
2.18
2.16

1.95
1.97
1.75

0.0 - 6.8
-0.1 - 6.6
0.0 - 6.2

F[2, 633] = 0.21, p = 0.81

82

Figure 2.3. Profile of mean and minimum daily mainstem water temperature from October 1 to May 31 of year
1 and year 2. Temperatures recorded at 11.2 rkm on the Kitimat River.

Figure 2.4. Profile of mean and minimum daily discharge in the Kitimat River in year 1 and year 2.

83

Table 2.2. Summary of ANOVA and Tukey multiple comparison tests comparing mean mainstem discharge
from October to May in year 1 and year 2 to mean daily historic flows from 1965 to 2012.

Year

Raw Summary
Mean SE
Range

1
2
Historic

109.7
161.7
111.8

ANOVA:

F[2, 725] = 19.93, p < 0.001

7.2 3.1 - 681.3
8.1 12.5 - 979.7
3.6 47.5 - 253

Tukey's Post-hoc Comparison
Comparison
P-value
Year 1 - Year 2
Year 1 - Historic
Year 2 - Historic

< 0.001
0.97
< 0.001

-

Correlations and Collinearity
Strong correlations were observed between the abiotic variables in both the
overwintering departure (Table 2.3) and spawning arrival datasets (Table 2.4). Correlations
were strongest between water temperature and photoperiod (r > 0.80). In the spawning
analysis, a correlation of moderate strength (r = 0.66, p < 0.001) was also observed between
photoperiod and discharge, though this correlation was considerably weaker in the
overwinter data set (r = 0.30, p < 0.001). Strong, significant correlations were also observed
between accumulated thermal units and discharge (r = 0.65, p < 0.001) and temperature (r
= 0.78, p < 0.001) in the spawning analysis (Table 2.4); these correlations were weaker in
the overwintering analysis (Table 2.3). The strength of the relationship between water
temperature and discharge was similar in both analyses, however the relationship was
negative in the overwintering analysis (r = -0.21, p < 0.001) and positive in the spawning
analysis (r = 0.21, p < 0.001). A negative correlation of moderate strength was observed
between discharge and fork length in the analysis of movement out of overwintering
habitats (r = -0.44, p < 0.001), and into spawning tributaries (r = -0.40, p < 0.001).

84

Analysis of VIF scores for the global overwintering and spawning models
demonstrated that collinearity was a serious issue between water temperature and
photoperiod. Thus, to reduce collinearity, water temperature and photoperiod parameters
were not included in the same candidate models. Quadratic terms for each abiotic variable
were tested; however, they did not significantly improve model fit and were not included in
any of the candidate models.

Table 2.3. Correlations between metrics included in the analysis of departure from overwintering habitats.

1
< 0.001
< 0.001
< 0.001
0.055
0.030
0.128
0.596

0.30
1
< 0.001
< 0.001
< 0.001
0.174
0.026
< 0.001

0.83
-0.21
1
< 0.001
0.030
0.219
0.918
< 0.001

ATU
0.90
0.49
0.57
1
< 0.001
0.020
0.030
< 0.001

Fork Length Distance Sex Mig.Type
-0.09
-0.25
0.10
-0.2
1
0.049
< 0.001
< 0.001

-0.10
-0.06
-0.06
-0.11
0.09
1
0.462
0.125

0.07
0.10
0.00
0.1
0.25
0.03
1
0.084

0.02
0.25
-0.16
0.15
-0.44
0.07
-0.08
1

Correlation

Photoperiod
Discharge
Temperature
ATU
Fork Length
Distance
Sex
Mig.Type

Photoperiod Discharge Temperature

P-Value

Parameter

Table 2.4. Correlations between metrics included in the analysis of arrival in to spawning tributaries.

1
< 0.001
< 0.001
< 0.001
< 0.001
0.437
0.059
< 0.001

0.66
1
< 0.001
< 0.001
0.000
0.827
0.111
< 0.001

0.80
0.21
1
< 0.001
0.516
0.475
0.340
0.254

ATU
1.00
0.65
0.78
1
< 0.001
0.430
0.040
< 0.001

Fork Length Distance Sex Mig.Type
-0.17
-0.24
-0.03
-0.18
1
0.295
< 0.001
< 0.001

0.04
0.01
0.03
0.04
0.05
1
0.124
0.003

0.09
0.08
0.05
0.10
0.20
-0.07
1
0.137

0.19
0.23
0.05
0.20
-0.40
0.14
-0.07
1

Correlation

Photoperiod
Discharge
Temperature
ATU
Fork Length
Distance
Sex
Mig.Type

Photoperiod Discharge Temperature

P-Value

Parameter

85

Overwintering Departure Models
A total of 47 candidate models for CCT were included in the overwintering analysis
to characterize departure from overwintering habitats between March 13 to May 7 (median
= April 7) (Figure 2.5). The number of temporal periods included in the analysis for each fish
ranged from 4 to 18, with an overall mean of 10.1 ± 3.0. Mean values of day length
recorded in each period ranged from 12.8 to 17.1 hr. Mean temperature and discharge
values ranged from 0.2 to 7.0 °C and 8.5 to 309.8 m3 s-1, respectively (Table 2.5; Figure 2.5).
Accumulated thermal units experienced by CCT during periods when movements were
completed ranged from 177.6 to 427.3 ATU. Measures of water temperature, discharge and
ATUs differed significantly between years during intervals when CCT moved out of
overwintering habitats (Table 2.5; Figure 2.5). Cutthroat included in the overwintering and
spawning analysis were primarily female (60%) and ranged in fork length from 331 to 460
mm (395.3 ± 34.9 mm). The mean ± SD total absolute distance radio tagged CCT travelled
from overwintering to spawning habitats was 9.7 ± 7.9 km, though this ranged from 1.1 to
37.0 km.
The results of the overwintering analysis are summarized in Table 2.6. Models that
included photoperiod primarily had lower AICc values than models that did not include
photoperiod; photoperiod was included in 9 of the top 10 models and the model with only
photoperiod was ranked 6th. The model with the lowest overall AICc value (AICc = 236.89)
consisted of photoperiod and fork length. This model indicates that photoperiod (β = 1.442,
SE = 0.248, P < 0.001) and fork length (β = 0.011, SE = 0.004, P = 0.003) significantly
influence when CCT depart from overwintering habitats (Table 2.7). An additional 3 models
86

had AICc values that differed by less than 2 and are considered to be probable candidate
models. The model with the second lowest AICc value (∆ AICc = 0.16) included photoperiod
(β = 1.413, SE = 0.198, P < 0.001) and distance travelled from overwintering to spawning
habitats (β = 0.060, SE = 0.024, P = 0.024). Confidence intervals of the top 2 models did not
include zero and all parameters were shown to have a significant effect. Together these two
models account for a total accumulated Akaike weight of 0.44. The third and fourth ranked
models were more complicated versions of the second and first ranked models,
respectively, and both contained negative, non-significant coefficient estimates for
discharge. Including the third and fourth ranked models increased the total accumulated
Akaike weight of the top models to 0.65. The area under the receiver operating curve was
greater than 0.86 for all four of the top ranked models, indicating that they had good
predictive ability.

Table 2.5. Summary of abiotic measures calculated for temporal intervals included in the overwintering
analysis. Tests for differences between years are presented in the final column.

Photoperiod
Temperature
ATU
Discharge

Combined
Mean SD
Range

Year 1
Mean SD
Range

Year 2
Mean SD
Range

14.8 0.8 12.8 - 17.1
4.4 1.1
0.2 - 7.0
276.0 50.8 177.6 - 427.3
112.9 80.6 8.5 - 309.8

14.6 0.7 13.2 - 15.9
4.7 0.7
2.5 - 5.8
258.2 46.1 177.6 - 343.2
56.9 25.2 8.5 - 81.4

15.1 0.9 12.8 - 17.1
4.1 1.4
0.2 - 7.0
296.3 49.2 204.5 - 427.3
176.4 74.4 59.0 - 309.8

Two-Sample T-Test
t(466.6) = -1.31, p = 0.19
t(428.0) = 9.59, p < 0.001
t(447.3) = -8.31, p < 0.001
t(343.3) = -17.91, p < 0.001

87

Figure 2.5. Environmental conditions and count of the number of fish moving per period in year 1 and 2. Each
period represents 4 days, starting on February 15. Line plots compare mean water temperature (Temp., °C),
3 -1
accumulated thermal units (ATU, sum of mean daily temperature), discharge (Flow, m s ), and day length
(Photo, hr) per period in year 1 and year 2. Histograms summarize the total number of CCT observed moving
out of overwintering habitats (OW) and into spawning tributaries (Spawn) during each period.

88

Table 2.6. Set of logistic regression candidate models used to estimate likelihood of movement out of
overwintering habitats for CCT radio tagged in the Kitimat River in year 1 and year 2. Standard errors in each
model were clustered by individual CCT. Fixed effect variables include: Photoperiod, a continuous measure of
mean civil day length (hr); Temperature and Discharge, measures of mean mainstem water temperature and
discharge, respectively; ATU, running sum of mean daily mainstem water temperature; Distance, measure of
the total absolute distance (km) each CCT travelled to spawn from final overwintering habitats; Mig.Type, a
dichotomous measure identifying mobile (1) and stationary CCT (0); Sex, a dichotomous variable identifying
male (0) and female (1) CCT, and; FL, a measure of the fork length (mm) of individual CCT.
Rank
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40

Model
Photoperiod + FL + Constant
Photoperiod + Distance + Constant
Photoperiod + Discharge + Distance + Constant
Photoperiod + Discharge + FL + Constant
Photoperiod + Sex + Constant
Photoperiod + Constant
Temperature + Discharge + Distance + Constant
Photoperiod + Mig.Type + Constant
Photoperiod + Discharge + Constant
Photoperiod + Discharge + Sex + Constant
Temperature + Discharge + Constant
Temperature + Discharge + FL + Constant
Photoperiod + Discharge + Mig.Type + Constant
Temperature + Discharge + Sex + Constant
Temperature + Discharge + Mig.Type + Constant
ATU + FL + Constant
ATU + Discharge + FL + Constant
ATU + Distance + Constant
ATU + Discharge + Distance + Constant
ATU + Mig.Type + Constant
ATU + Sex + Constant
ATU + Constant
ATU + Discharge + Sex + Constant
ATU + Discharge + Mig.Type + Constant
Temperature + Distance + Constant
Temperature + Constant
Temperature + Sex + Constant
Temperature + Mig.Type + Constant
Temperature + FL + Constant
Discharge + Constant
Discharge + FL + Constant
Discharge + Distance + Constant
Discharge + Sex + Constant
Discharge + Mig.Type + Constant
Distance + Constant
FL + Constant
Sex + Constant
Mig.Type + Constant
Sex + FL + Distance + Constant
Mig.Type + FL + Distance + Constant

LL

n df k

ROC

AICc

∆ AICc

Wi Acc. Wi

-114.404 473 2 4
-114.485 473 2 4
-114.152 473 3 5
-114.238 473 3 5
-115.766 473 2 4
-116.799 473 1 3
-114.973 473 3 5
-116.169 473 2 4
-116.384 473 2 4
-115.450 473 3 5
-116.886 473 2 4
-115.897 473 3 5
-115.934 473 3 5
-116.067 473 3 5
-116.811 473 3 5
-119.055 473 2 4
-118.746 473 3 5
-119.864 473 2 4
-119.314 473 3 5
-120.855 473 2 4
-120.952 473 2 4
-121.976 473 1 3
-120.450 473 3 5
-120.517 473 3 5
-121.961 473 2 4
-123.041 473 1 3
-122.654 473 2 4
-122.880 473 2 4
-122.948 473 2 4
-149.425 473 1 3
-148.579 473 2 4
-148.965 473 2 4
-149.015 473 2 4
-149.055 473 2 4
-152.804 473 1 3
-152.914 473 1 3
-152.923 473 1 3
-153.090 473 1 3
-152.360 473 3 5
-152.655 473 3 5

0.86
0.87
0.87
0.86
0.87
0.86
0.85
0.86
0.85
0.86
0.85
0.85
0.86
0.85
0.85
0.84
0.84
0.84
0.85
0.83
0.84
0.83
0.85
0.83
0.82
0.82
0.82
0.82
0.82
0.65
0.65
0.64
0.63
0.64
0.52
0.53
0.52
0.51
0.55
0.53

236.89
237.06
238.43
238.60
239.62
239.65
240.07
240.42
240.85
241.03
241.86
241.92
242.00
242.26
243.75
246.19
247.62
247.81
248.76
249.79
249.99
250.00
251.03
251.16
252.01
252.13
253.39
253.85
253.98
304.90
305.24
306.02
306.12
306.20
311.66
311.88
311.90
312.23
314.85
315.44

0.00
0.16
1.54
1.71
2.72
2.75
3.18
3.53
3.96
4.13
4.96
5.03
5.10
5.37
6.86
9.30
10.73
10.92
11.86
12.90
13.09
13.11
14.13
14.27
15.11
15.24
16.50
16.95
17.09
68.01
68.35
69.12
69.22
69.30
74.77
74.99
75.00
75.34
77.95
78.54

0.23
0.21
0.11
0.10
0.06
0.06
0.05
0.04
0.03
0.03
0.02
0.02
0.02
0.02
0.01
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00

0.23
0.44
0.55
0.65
0.71
0.77
0.81
0.85
0.88
0.91
0.93
0.95
0.97
0.99
0.99
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00

89

Table 2.7. Diagnostic summary of overwintering candidate models with AICc values less than 2. Fixed effect variables include: Photoperiod, a continuous
measure of mean civil day length (hr); Discharge, a measure of mean mainstem discharge; Distance, measure of the total absolute distance (km) each CCT
travelled to spawn from final overwintering habitats, and; FL, a measure of the fork length (mm) of individual CCT.

90

Spawning Models
The same 47 CCT in the overwintering analysis were also included in the spawning
analysis. The median date that CCT arrived in spawning tributaries ranged from April 6 to
May 11, with peak spawning (median) occurring on April 27. Abiotic metrics were calculated
for a total of 15 four-day temporal periods encompassing March 11 to May 9. Mean
measures of day length calculated in each period ranged from 12.9 to 16.8 hr. The mean
values of mainstem water temperature, accumulated thermal units and discharge ranged
from 12.9 to 17.1 °C, 177.6 to 427.3 ATU and 8.5 to 309.8 m3 s-1, respectively. In year 1,
movements into spawning tributaries occurred at significantly lower values of photoperiod,
accumulated thermal units and discharge (Table 2.8; Figure 2.5). Abiotic metrics are the
same as those used in the overwintering model.
Candidate models tested in the spawning analysis are summarized in Table 2.9 and
Table 2.10. Accumulated thermal units dominated the top spawning models; ATU was
included in 7 of the top 10 models and the model with only ATU ranked 5th. The spawning
model with the lowest AICc value had an Akaike weight of 0.25 and suggests that
movement into spawning tributaries is influenced by accumulated thermal units (β = 0.027,
SE = 0.003, P < 0.001) and migration type (β = - 0.781, SE = 0.347, P < 0.024) (Table 2.10).
Two additional models had ∆ AICc values less than 2 and are considered as good as the top
model. The second ranked model (∆ AICc = 1.66) also included migration type (β = -0.771, SE
= 0.335, P = 0.021), though ATU was replaced by photoperiod (β = 1.677, SE = 0.209, P <
0.001). The final model had a ∆ AICc value of 1.82 and contained accumulated thermal units
(β = 0.028, SE = 0.004, P < 0.001), migration type (β = - 0.747, SE = 0.350, P = 0.033) and
91

discharge. Except for discharge in the third model, all parameters were significant and did
not include zero within their confidence intervals. Area under the ROC curves for all three
top models were greater than 0.85, indicating that they were of high predictive value.

Table 2.8. Summary of measures of photoperiod (hr), temperature (°C), thermal experience (ATU, °C) and
3
discharge (m/s ) calculated for temporal intervals included in the spawning analysis.

Photoperiod
Temperature
ATU
Discharge

Combined
Mean SD
Range

Mean

Year 1
SD
Range

15.8 0.8 13.7 - 17.1
5.2 0.8
2.9 - 7
335.4 55.2 205 - 427.3
136.1 75.9 8.5 - 309.8

15.5 0.9 13.7 - 16.8
5.3
0.6
4.2 - 6.7
321.6 57.6 205 - 410.7
82.9 36.7 8.5 - 181.7

Year 2
Mean SD
Range
16.0 0.8 14.6 - 17.1
5.1 1.0
2.9 - 7
351.1 48.9 268.1 - 427.3
196.6 62.2 126.9 - 309.8

Two-Sample T-Test
t(426.4) = -7.39, p < 0.001
t(415.9) = 0.43, p = 0.67
t(431.4) = -7.98, p < 0.001
t(263.8) = 12.87, p < 0.001

92

Table 2.9. Set of logistic regression candidate models used to estimate likelihood of movement into spawning
tributaries for CCT radio tagged in the Kitimat River in year 1 and year 2. Standard errors in each model were
clustered by individual CCT. Fixed effect variables include: Photoperiod, a continuous measure of mean civil
day length (hr); Temperature and Discharge, measures of mean mainstem water temperature and discharge,
respectively; Distance, measure of the total absolute distance (km) each CCT travelled to spawn from final
overwintering habitats; Mig.Type, a dichotomous measure identifying mobile (1) and stationary CCT (0); Sex, a
dichotomous variable identifying male (0) and female (1) CCT, and; FL, a measure of the fork length (mm) of
individual CCT.

93

Table 2.10. Diagnostic summary of spawning candidate models with AICc values less than 2. Standard errors in each model were clustered by individual CCT.
Fixed effect variables include: Photoperiod, a continuous measure of mean civil day length (hr); ATU, a measure of cumulative mean daily mainstem water
temperature; Discharge, measure of mean mainstem discharge, and; Mig.Type, a dichotomous measure identifying mobile (1) and stationary CCT (0).

94

DISCUSSION

The overwintering and spawning analyses demonstrate that both abiotic and biotic
factors influence migratory behaviours of CCT. Additionally, responses to environmental
stimuli appeared to differ between migration from overwintering habitat and migration to
spawning areas. Spawning migrations were initiated when CCT depart from overwintering
habitats and the results of this analysis demonstrated that photoperiod and fork length
were the primary variables which correlate when movements occur. In contrast, the results
suggest that arrival in spawning tributaries is most strongly influenced by thermal
experience and migration type. Collinearity between environmental variables was a serious
issue in this study and the influence of abiotic effects must be considered cautiously.
Overwinter Analysis
The overwintering analysis identified 4 top candidate models that were able to
explain when CCT would depart overwintering habitats. Photoperiod, distance to spawn,
fork length and discharge were identified as the most influential variables. Photoperiod was
the most important variable and appeared in each of the top 4 models, however, it was
strongly correlated with thermal experience and water temperature. Thus, the effect of
photoperiod should be considered cautiously.
Photoperiod dominated the top models and was clearly the single abiotic variable
that best predicted when CCT would move out of overwintering habitats. Models that
included photoperiod consistently ranked higher (had lower AICc values) than models that
did not, including when photoperiod was modelled independently. The results of this study
are novel because they suggest that photoperiod was a better predictor of when CCT would
95

move out of overwintering habitats than other variables that have commonly been linked
with migratory movements such as water temperature and discharge. Photoperiod has
been shown to influence migratory behaviour by cueing physiological changes associated
with sexual maturation and smolting and by promoting positive rheotaxis (Dodson and
Young 1977, Duston and Bromage 1986, Duston and Saunders 1990, Björnsson et al. 1994,
Martin et al. 2012). However, it is difficult to link physiological changes associated with
photoperiod to the migratory behaviours that were observed. Sexual maturation is not an
immediate process and will have been initiated several months before the earliest
movement dates included in the analysis. Additionally, CCT moved both up and
downstream from overwintering to spawning habitats suggesting that rheotaxis alone did
not induce the observed migrations. Thus, if photoperiod is having a direct effect on
movements out of overwintering habitats it is having an effect that has not been previously
described. Additional research focusing specifically on overwintering behaviours, and which
includes physiological as well as biological measures is likely to provide greater insight into
this phenomenon.
Collinearity between abiotic variables is often recognized as one of the greatest
factors limiting the ability to interpret environmental influences on migratory behaviours
(Trepanier et al. 1996). Indeed, collinearity was a serious issue in my study. Photoperiod
changes were highly correlated with temperature (r = 0.83) and even more highly correlated
with thermal experience (r=0.90); a weaker, but still significant correlation was observed
between photoperiod and discharge (r=0.30). A substantive argument could be made that

96

water temperature rather than photoperiod may have been driving the observed
behaviours.
Models containing water temperature and photoperiod were of similar predictive
ability, as evidenced by similar ROC values. Additionally, the steady nature by which day
length increased during, and leading up to the period when movements were observed
suggests that CCT responded to a threshold rather than a specific change in photoperiod.
Threshold responses to day length have not been described for salmonids; however, they
have been well documented in response to water temperature. In fact, water temperature
is often recognized as a primary trigger initiating short duration spawning migrations among
salmonids (e.g. Jensen et al. 1986, Swanberg 1997, Stephan and Zurstadt 2004, Svendsen et
al. 2004). It is therefore a very real possibility that CCT responded to water temperature
rather than photoperiod, but that the strong progressive nature of photoperiod promoted
its significance within the models and resulted in photoperiod being the best predictor of
movement from overwintering habitats.
Fork length was also identified as a variable that influenced the timing that CCT
moved out of overwintering habitats. In my study, larger CCT initiated movements out of
overwintering habitats earlier during each winter. In year 1, radio tagged CCT were
significantly larger and spawned earlier than CCT in year 2, however, it is unlikely that fork
length appeared in the top models due to these differences between years. Indeed, a visual
examination of the data demonstrated that the relationship was clear in each year and
similar size gradients have been recorded for CCT as well as other salmonids and charr.
Yanusz (1997) observed a similar pattern among CCT emigrating from Sitkoh Lake to spawn
97

in small coastal streams of SE Alaska. Size gradients have also been described during studies
of the migratory behaviours of steelhead, bull trout, brook trout and Atlantic salmon
(Swanberg 1997, Curry et al. 2002, Dahl et al. 2004, McLean et al. 2005). Early arrival of
larger fish may promote size assortative mating (Hanson and Smith 1967). However, more
recent studies employing genetics have demonstrated that size may have less of an effect
on reproductive success than previously believed (Garant et al. 2001, Seamons et al. 2004,
Dickerson et al. 2005, Costello 2006). Indeed, precocious stream resident male CCT have
been shown to successfully reproduce with larger, migratory female CCT (Costello 2006).
In my study, early departure from overwintering habitats did not confer earlier
arrival within spawning tributaries. Radio tagged CCT that departed overwintering habitats
earlier took relatively longer to enter spawning tributaries. This suggests that larger, earlier
departing CCT either travelled further to spawn, and/or travelled to staging positions prior
to spawning. The significant positive correlation between fork length and distance travelled
to spawn (r = 0.09, p = 0.049, Table 2.3) demonstrates that larger CCT generally travelled
further. The fact that the second-top overwintering model identified distance as a
significant predictor of overwintering departure timing further reinforces this observation.
In addition, the relocation data described in chapter 1 provides considerable evidence that
CCT used staging habitats prior to spawning. Staging may be preferred by larger CCT to
ensure that final movements into spawning tributaries occur under suitable stream
conditions. For instance, selection of higher, more turbid flows may reduce predation
during migrations (Svendsen et al. 2004 and references within). Movements out of
overwintering habitats roughly coincide with the April emigration of coho and Chinook
98

salmon smolts (Macdonald and Shepherd 1983). It is therefore also possible that larger,
presumably more piscivorous CCT move out of overwintering habitats earlier to capitalize
upon this important seasonal food source prior to spawning. Finally, given that female CCT
were significantly larger than males, the observed size gradient may be due to differences in
the date that male and female CCT departed overwintering areas. Sex did appear in the 5th
ranked overwintering model (∆ AICc = 2.72), however it’s effect was non-significant and
weakly negative suggesting that males moved earlier than females.
The second ranked overwintering model suggests that the absolute total distance
CCT travelled to spawn had a significant positive effect on the likelihood that an individual
would move out of an overwintering habitat. Date when fish initiate movements toward
spawning areas was described in an earlier study on fall spawning bull trout. Bahr and
Shrimpton (2004) found that adult bull trout initiated a directed movement earlier in the
season if they were further from spawning locations. To my knowledge, my study is the first
to find that distance from spawning locations was associated with timing of overwintering
departure for a spring spawning salmonid. As described earlier, the relationship may be
associated with larger fish overwintering in locations further from the spawning locations.
Consequently, CCT travelling further to spawn are more likely to move out of overwintering
habitats at an earlier date than CCT that overwintered closer to spawning habitats, a
relationship observed during both years. Early departure from overwintering habitats did
not confer early spawning and many CCT travelled great distances to staging habitats prior
to spawning. Thus, it is likely that CCT travelling further initiated migrations earlier to be
situated closer to spawning habitats in the period immediately prior to spawning. Moving
99

close to spawning tributaries would ensure that CCT are better able to respond to the
conditions of the spawning stream and may also increase the likelihood of finding a mate,
particularly if spawning populations are low.
The final parameter that appeared within the top set of overwintering models was
discharge. In the two models that included discharge, it had a weakly negative effect
suggesting that CCT are moving as discharge declines; the confidence intervals however
were large and overlapped zero indicating that discharge had little informative power. Thus,
even though discharge did appear within the top-ranking models, it’s effect appears to be
small. Given that the longest distance migrations were from overwintering to staging and
spawning habitats a response to flow should be expected. Indeed, a visual examination of
the discharge profile shows that movements out of overwintering habitats were initiated
after flows began to increase in the spring. However, from overwintering habitats CCT
primarily moved through the mainstem and major tributaries and it is likely that migrations
through these relatively large waterbodies are possible at a wide range of flows. Evidence
that CCT can complete overwintering migrations at a wide range of flows is provided by the
fact that CCT completed movements out of overwintering habitats at significantly higher
flows in year 2. This discrepancy between years may also explain the insignificant effect of
discharge as an elevated response in one year may have been muted by a reduced response
in the second year. It is also possible, however, that flows throughout the study period did
not restrict movements out of overwintering habitats. Longer term datasets are likely
necessary to fully understand how CCT are responding to flow.

100

Spawning Analysis
Three top models were identified as being able to explain when CCT would arrive in
spawning tributaries. These three models identified thermal experience, migration type,
photoperiod and discharge as the variables having the strongest effect on spawning
migrations. As with the overwintering analysis, collinearity between thermal experience,
water temperature and photoperiod require that interpretation of the effects of these
variables be considered with caution.
Thermal experience appeared in 2 of the 3 top spawning models and was identified
as the primary abiotic variable influencing migrations into spawning habitats. The inclusion
of thermal experience in the top models indicates that CCT are more likely to move into
spawning tributaries as cumulative degree-days increase. This suggests that spawn timing is
influenced by prevailing environmental conditions and may explain why CCT moved into
spawning habitats significantly earlier in year 1. Thermal experience is likely to affect
migration timing by influencing when CCT mature. Certainly, water temperature has been
shown to influence rates of sexual maturation (Hokanson et al. 1973) and warmer
antecedent temperatures have been associated with early seaward migration (Holtby 1988)
and spawn timing (Dahl et al. 2004). Along with photoperiod, water temperature functions
to synchronize the timing of important life history events with environmental conditions
(Hoar et al. 1983). For instance, changes in day length have been shown to control the
timing of annual life history events, such as spawning, by initiating important physiological
processes, such as gametogenesis. However, it is water temperature that controls the rate
at which maturation occurs and which therefore ensures that life history events, such as
101

spawning, occur under favorable conditions during a given season. The fact that water
temperatures were warmer and that fish spawned earlier in year 1 reinforces the likelihood
that thermal experience influenced spawn timing by affecting maturation rates. Future
research that applies bio-tracking technologies is required to better understand how
thermal experience influences migration behaviours.
During each winter, radio tagged CCT displayed one of two overwintering
behaviours. They either remained stationary within a single overwintering habitat, or were
mobile and moved between multiple aggregations. Migration type appeared in the top two
spawning models and was identified as the most important biological parameter for
predicting when CCT would arrive in spawning tributaries. Coefficient estimates of
migration type were consistently negative and of moderate strength, indicating that
stationary CCT were more likely to move into spawning tributaries earlier than mobile CCT
in each temporal period. Migration type appeared within each of the top spawning models,
demonstrating that CCT in each behavioural group showed differing responses to thermal
experience, photoperiod and discharge. This discrepancy in behavioural responses between
groups adds additional support to the notion that CCT in each group are displaying unique
behavioural strategies.
The mechanisms contributing to the behavioural differences between groups are
not clear and require further research. However, there is evidence to suggest that physical
characteristics, age, and/or life experience may have contributed to the observed
behavioural differences. Stationary CCT were significantly larger and older than mobile CCT.
The difference in age and size may indicate that stationary CCT were repeat spawners
102

and/or had greater experiential knowledge. If this is the case then the observed discrepancy
in behaviours may exist along a size gradient. Further research is required to assess the
perceived size gradient and to better understand how and why observed differences in
behaviour exist.
Photoperiod was shown to have a significant positive effect on spawning timing
within one of the three top candidate models, suggesting that the likelihood CCT will move
into spawning tributaries increases with longer day length. Photoperiod has been shown to
affect the timing of spawning migrations by stimulating rheotaxis and/or by cueing
physiological processes related to sexual maturation. For the reasons described in the
overwintering analysis, however, it is unlikely that these processes had a direct effect on the
timing of CCT movement into spawning habitats. Furthermore, if photoperiod had a direct
effect on the timing of spawning it should be expected that spawning movements would
not differ between years. Movement times differed in this study between years and
suggests that photoperiod either had a novel influence on spawning behaviours, or more
likely, that the nature by which photoperiod increased throughout the study period
promoted its significance within the model.
Collinearity between water temperature and photoperiod was a serious issue in this
study and has been shown to greatly complicate, and limit the strength of interpretations of
environmental influences on behaviour. Given the collinearity observed in this study, it
cannot be ruled out that the fish may in fact be responding to changes in parameters that
are associated with photoperiod, such as water temperature and thermal experience.
Certainly, the importance and prevalence of thermal experience within the top model set
103

suggests that water temperature is having a significant effect on when CCT are arriving in
spawning tributaries.
Discharge was the only parameter included in the top set of models that was not
significant, suggesting that movements into spawning tributaries were not influenced by
flow. A stronger response to flow was certainly expected in this study given that CCT are
known to, and were observed to, spawn in the upper most accessible reaches of small first
and second order tributaries. Flow may have had an insignificant effect on spawning
behaviour for several reasons. First, flows in year 1 were significantly lower than in year 2
and it is possible that behavioural responses varied between years. Indeed, a visual
examination of the data reveals that flows were more variable in year 2 and that CCT in that
year completed migrations during high flow events. Flows during year 1, however, were
more stable and the primary movement of CCT into spawning tributaries occurred between
flow events. Therefore, if CCT showed a strong response in one year, but not both years, it
is possible that the lack of response would reduce the significance of flow within the model.
It is also possible that flows in each year were above a threshold required to access
spawning habitats. In this study, CCT were observed travelling to spawning habitats in the
upper most accessible reaches of first and second order tributaries during each year. The
geography of the Kitimat River may also permit CCT to move to the upper most accessible
spawning habitats at a wide range of flows. In both years of the study, the majority of
spawning was observed within the lower and middle reaches of the Kitimat watershed,
where the valley is at its widest and accessible reaches of tributaries are relatively short,
low gradient and influenced by groundwater (Macdonald and Shepherd 1983, Reese104

Hansen 2004). If flows did not restrict access to spawning habitats, then a minimal response
to flow should be expected.
Finally, this study used mainstem discharge as a surrogate of flows within small
tributaries. It is possible that a stronger response to flow would have been observed if flows
had been measured directly within tributaries. Mainstem discharge should reflect the
general behaviour of tributary flows; however, a temporal lag will certainly exist between
tributary and mainstem flows. Previous research has demonstrated that responses to flows
vary between years, populations and species. Given this variability, the appearance of flow
within the top ranked model set should be considered to indicate that flow may have an
effect on the spawning behaviours of CCT. To better understand how flow affects spawning
behaviour research that applies a longer-term dataset is recommended.
Implications
The results of the overwintering and spawning analyses demonstrate that factors
influencing migrations from overwintering to spawning habitats were complex and
influenced by both biotic and abiotic variables. Coastal cutthroat trout are arguably the
least understood species of salmonid (Trotter 2008) and the results of this study provide
insight into some of the variables that appear to be structuring migratory behaviours within
the Kitimat River. Previous research into the migratory behaviours of salmonids have
demonstrated that responses to biotic and abiotic cues are highly variable within and
among species as well as over time. Thus, the results presented in this study should be
regarded as a point of reference and are not likely to reflect range wide trends for the
subspecies.
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In addition to the metrics that were included in this analysis, strong correlations are
likely to exist among unmeasured/unmodeled environmental variables which may influence
movement. Movement studies often focus upon flow and temperature while ignoring
covariates that may also have a strong influence on movement (Trepanier et al. 1996). For
instance, rising flows generally increase turbidity which may reduce predation during
spawning migrations (Gregory and Levings 1998). Additionally, flows may promote
movement towards foraging habitats if they increase invertebrate drift (Romero et al.
2005), or to off-channel cover habitats if they are suitably high (Harper and Farag 2004).
Thus, although these factors were not assessed in my study, it is possible that they too may
have influenced behaviours.
Due to the collinearity among environmental parameters the results of this analysis
should not be considered to reflect cause and effect. This should not be implied to
underscore the presented results but rather to ensure that they are interpreted with
caution and an understanding that changes in modelled environmental parameters will
influence a variety of additional unmodeled environmental metrics. Thus, changes in day
length stimulate migratory behaviours of CCT in the Kitimat River, but migration may or may
not be in direct response to photoperiod.

106

EPILOGUE

Coastal cutthroat trout are not fished commercially and the recreational fishery for
the subspecies is limited, relative to other Pacific salmonids. As a result, there has been
minimal systematic research into their ecology and behaviour. All too often, stream-specific
information is anecdotal or has been collected indirectly during studies of other species
(e.g. McCubbing 2002). The diverse array of habitats occupied by coastal cutthroat trout
and the varied life history strategies displayed by the subspecies have added to the
challenges in extrapolating range-wide trends. For these reasons, watershed-specific, or at
least regional evaluations of CCT are required to assess and manage stocks appropriately.
This is particularly important in British Columbia, which contains the majority of the species
native range. To date, however, the research on the migration patterns and movement
behaviours has occurred overwhelmingly at the extremities of the subspecies range
(specifically, in Washington, Oregon and Alaska).
Patterns of trophic migrations, however, found for other species of salmonids may
be applicable to CCT. As individual fish move through different life history stages they are
not only capable of, but also require, access to different types of habitats and food sources.
The movement patterns exhibited by salmonids can, therefore, be considered as variations
on a theme that ensures the successful linking of spawning and rearing habitats with areas
for feeding and overwintering. Northcote’s (1997b) migratory/residency spectrum model,
for example, provides a functional description of general migratory behaviours that may be
applied to CCT from all life history strategies and suggests that CCT migrate between
feeding, wintering and spawning habitats to meet their foraging, refuge and reproductive
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requirements. The movements and behaviours observed throughout this study fit within
the migratory/residency spectrum model developed by Northcote (1997b). Refuge
migrations were completed in the fall when CCT moved from mainstem and estuarine
foraging habitats to overwintering habitats. In the spring, reproductive migrations from
overwintering to spawning habitats were followed by trophic migrations to mainstem and
estuary foraging habitats. Although Northcote’s model provides a functional overview of
general movement patterns, it is unable to account for the complexity and diversity of
individual trout movement.
Behaviours observed in this study can be generally characterized as either
synchronous movements within the population, or individual movements. Synchronized
behaviours fit within Northcote’s model and were associated with life history events,
occurring when tagged CCT exhibited movements of similar purpose, magnitude and timing.
Synchronized movements were most apparent in the spring when CCT moved from
overwintering habitats to spawn, and from spawning tributaries to the estuary. In contrast,
individual movements cannot be accounted for by Northcote’s model, and may be
opportunistic or responsive to environmental cues. Individual movements were most
apparent throughout the winter, by mobile CCT that made frequent up- and downstream
movements. The duration of time that CCT spent in marine environments and the timing
that they returned to fresh water was also individual, varying considerably among sea-run
CCT.
Distinguishing between synchronous and individual behaviours is important.
Understanding the factors influencing individual behaviours will contribute to our
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understanding of whether the inherent individuality of CCT is a product of, or reason for,
the species’ unique and diverse life history behaviours. Movement studies, however, that
focus on ecologically sensitive time periods, when movements are often synchronized, are
more likely to identify significant biological relationships (Tetzlaff et al. 2005). It is
recommended, therefore, that future research on CCT focus on synchronized, life history
associated behaviours as they are most likely to be predictable and consistent among
populations. Once our understanding of the factors shaping the basic life history behaviours
of CCT are better understood it is likely that the stimuli influencing individual behaviours
will become clearer.
Recent evidence suggesting that individuals may switch between migratory
strategies in response to variable environmental conditions has led Johnson et al. (2010) to
suggest that there may be a certain degree of phenotypic plasticity associated with life
history form. These authors have proposed that sympatric populations of migratory and
stream resident CCT may exist along a life history continuum rather than in fixed,
predetermined states. A flexible life history strategy that has permitted individuals to
modify their behaviours in response to environmental stochasticity may act to increase the
resiliency of CCT populations and may have contributed to the diverse array of habitats they
are currently found within (Northcote 1997b).
My research has provided evidence that CCT can, and do, shift behavioural
strategies. Indeed, a portion of CCT tracked throughout both winters displayed stationary
behaviours in year 1 and mobile behaviours in year 2. Though limited in number, the
behavioural shift between years was clear and is further supported by the significant
109

difference in the relative proportion of CCT displaying stationary and mobile behaviours in
each year. Certainly, Westslope cutthroat trout have been documented to display similar
stationary and mobile overwinter behaviours which may indicate that these strategies are
more common than has been previously recognized (Brown 1999). In my study, stationary
CCT were significantly larger than mobile CCT. It is unlikely however, that size was the
primary factor structuring the proportion of CCT displaying each overwintering strategy
given that relatively larger year 1 stationary CCT were observed to display mobile
behaviours in year 2. Thus, it was more likely that environmental conditions, or some other
external stimuli (i.e. environmental, or competition/resource related) influenced overwinter
behaviours. To better understand the prevalence of stationary and migratory winter
behavioural strategies, and to gain insight into the factors that may stimulate shifts
between strategies will require additional research. The observed shift and change in
proportion of CCT that displayed different behaviours in each year, however, suggest that
these strategies are plastic, rather than fixed traits.
It is likely that the wandering, individual nature of CCT may have influenced the
subspecies current distribution, and likely facilitated use of the full range of available
habitats within a watershed. The recolonization of previously inaccessible habitats was
directly observed in my study. Indeed, multiple CCT were observed spawning upstream of a
highway crossing that had recently been modified to permit fish passage. Additionally,
spawning within multiple streams occurred within 100 m of impassable barriers suggesting
that CCT were moving as far upstream as physically possible. These observations
demonstrate the benefits that will be realized by management activities that aim to
110

maximize habitat availability. Indeed, Magee et al. (1996) report that cutthroat trout redd
density is correlated with the quantity and quality of spawning habitats. Effective
population size is an indicator of resiliency to stochastic events (Newman and Pilson 1997).
A strong positive correlation between available spawning area and effective population size
in Chinook salmon (O. tshawytscha) was reported by Shrimpton and Heath (2003). These
findings demonstrate the benefits that will be realized by management activities that aim to
maximize available habitat for spawning.
Conservation Concerns
The exposure of CCT to recreational fisheries in the Kitimat watershed is a
conservation concern. Arguably, CCT are most vulnerable to angling throughout the winter,
when aggregated in overwintering habitats. Salmon and steelhead bait fisheries, however,
also pose considerable risk to CCT. Bait fisheries for CCT have been associated with high
mortality due to “deep hooking” (Mongillo 1984, Pauley and Thomas 1993, Gresswell and
Harding 1997) and incidental mortality was observed during this study when artificially
scented plastic worms were used as bait. Deep hooking was observed when angling with
roe; however, it was less frequent and no mortalities were directly attributed to the use of
roe. To reduce mortality associated with “deep hooking” the use of artificial plastic worms is
discouraged. Relative to bait, angling by lure and fly should reduce capture rates and
mortality of CCT (Schisler and Bergersen 1996). Additional research (i.e. angler surveys) is
recommended to quantify the exposure of CCT to recreational fisheries and assess the risks
to CCT associated with varying angling methods.

111

As with other species, CCT continue to feed throughout the winter and are
particularly vulnerable to angling as they aggregate within deep, slow moving pools (Cunjak
and Power 1987, White and Harvey 2007). Habitats with these characteristics are few and
far between within the Kitimat watershed. Thus, CCT aggregated in the same locations
during both winters and occupied all habitats with these characteristics. Of concern,
however, is the fact that these overwintering habitats are known, readily accessible and
frequently targeted by anglers. Thus, the seasonal dependence on these habitats has
indirectly increased angling pressure and efficiency. Presumably, CCT aggregate in
overwintering habitats to mitigate the stresses associated with winter environmental
conditions. However, capture by hook and line is a physiologically stressful event (Ferguson
and Tufts 1992, Bartholomew and Bohnsack 2005) and CCT that remain in aggregations are
likely to be captured more than once in a single winter (personal observation). Angling
activities that increase stress to aggregated CCT therefore diminish the functionality of
overwintering habitats to provide refuge. It is also possible that angling has affected
behaviours and that mobile CCT move between habitats in response to, or to escape from
angling.
Angling pressure on overwintering CCT is likely to vary with environmental
conditions. Relatively warm winters may increase angling pressure on CCT as ice cover will
be minimal and feeding rates will be elevated. Conversely, cooler winters may decrease
angling success due to the combination of reduced feeding rates and increased ice cover,
although evidence of ice fishing was apparent at multiple overwintering habitats used by
CCT. Thus, uncharacteristically warm winters may warrant consideration of additional
112

angling regulations specific to CCT. The relative ease at which aggregated CCT are captured
is attractive, particularly to new anglers. Conversations with recreational anglers targeting
overwintering CCT indicated that catching multiple CCT in an area over a short period
contributed to the belief that Kitimat River CCT were abundant. The status of CCT
populations in the Kitimat River, however, is unknown; this false assumption may promote
illegal harvesting of CCT (personal observation). Tools that increase awareness of CCT
behaviours and promote self-regulation of harvesting guidelines are recommended as a
means of mitigating the potential for illegal harvesting of overwintering CCT.
The steelhead fishery in the Kitimat River runs from late March to mid-May and is
primarily concentrated in the mainstem of the Kitimat River and the 3 largest tributaries
(Hirsch Creek, Big Wedeene and Little Wedeene). Angling was not conducted during the
steelhead fishery and anecdotal information on exposure to, and rates of, bycatch are
limited. Mobile tracking occurred frequently during the steelhead fishery and demonstrated
that CCT were concentrated in the lower and middle sections of the river. Given that
steelhead frequently targeted in this area, it is likely that CCT are also often captured. The
steelhead fishery directly coincides with the CCT spawning period and CCT may be removed
from the population in critical spawning tributaries (excluding CCT staging in the mainstem
and accessible reaches of the 3 largest tributaries). Fluvial CCT are perhaps more exposed to
the fishery than sea-run CCT which moved directly towards the estuary after spawning.
Thermal experience was identified as a key variable influencing the timing that CCT arrived
within spawning tributaries. Thus, exposure to the steelhead fishery may be elevated during
warmer years if fluvial CCT spawn and return to the mainstem earlier. Relative to gear that
113

is used during the salmon fishery, angling equipment used for steelhead is typically smaller
and more appropriate to CCT. Relative to the salmon fishery, the use of bait in the
steelhead fishery is likely to increase incidental mortality of CCT due to the smaller size of
hooks that are used.
Research Limitations
Aerial tracking flights were conducted infrequently during the salmon fishery and
radio tagged fish provided limited insight into the behaviours of CCT in the late summer and
fall. Sampling, however, was conducted extensively during the salmon fishery and
demonstrated that CCT were widely distributed throughout the watershed. Although
bycatch data was not formally collected from recreational salmon anglers, anglers were
frequently questioned about CCT and conversations suggest, anecdotally, that CCT were
captured as by-catch but that capture rates were relatively low. Sampling data corroborates
this assertion, catch-per-unit-effort (CPUE) was relatively low despite using gear, and
targeting habitats, specific to CCT. Thus, it is likely that CPUE of anglers targeting salmon will
be further reduced given that they are using larger gear and targeting habitats specific to
salmon (though habitat often overlaps, particularly with coho salmon). However, these
findings should be interpreted with caution. Despite the reduced CPUE, the salmon fishery
is the most popular recreational fishery on the Kitimat River and the sheer volume of
recreational anglers in the watershed at this time suggests that a disproportionately large
number of CCT are likely to be captured as bycatch.
The status of the Kitimat River CCT population is unknown, and stock assessment
activities have been limited by a general lack of knowledge of the timing and location of
114

spawning in the watershed. In my study, radio tagged CCT spawned throughout the lower,
middle and upper watershed in April and May. Table A2.4 summarizes the location and
timing that radio tagged CCT spawned and should be consulted if stock assessment
activities are considered in the Kitimat River watershed. Spawn timing differed between
years and thermal experience was identified as a significant predictor of spawn timing.
Thus, assessment programs should consider seasonal environmental conditions when
defining monitor timing as warmer winters may stimulate CCT to spawn earlier.
Tracking studies, however, assume that tagged individuals will display behaviours
that are representative of the greater population (Ramstad and Woody 2003). The surgical
implantation of radio transmitters is an invasive procedure and may affect fish behaviour.
Once CCT were tagged, the likelihood of recapturing, resampling, or even directly observing
an individual was low and there was little opportunity to assess the condition of tagged fish.
One advantage of surgical implantation is that deleterious effects of tagging should be
observed within a relatively short period (i.e. wounds will heal, or if, infected will likely
cause mortality). Thus, the likelihood that tagging affected behaviour should have
decreased with time. In my research, radio tagged CCT spawned 3.5 to 8 months after
tagging and it was therefore assumed that CCT that survived to spawn were not harmed by
the surgical procedure and that their behaviours were representative of the greater
population.
Coastal cutthroat trout are often characterized by their ability to adapt to local
environments. Likely, this adaptation has contributed to the diverse array of habitats and
behaviours exhibited by CCT. The variety of behavioural responses that local adaptation has
115

facilitated, however, hamper our ability as researchers and fisheries biologists, to predict
how CCT populations will behave. While broad generalizations can be made, watershed
scale research is necessary to understand even basic biological processes. The findings
presented in my research will contribute to our ability to make broad generalizations about
the species, however specifics, such as the timing of spawning and responses to
environmental stimuli should be expected to vary among CCT populations.
Given how little we truly know about CCT, and how vulnerable the species appears
to be to overharvesting and habitat degradation it is essential that fisheries managers err on
the side of caution when considering future developments that may affect CCT habitat and
fisheries regulations that may promote harvesting. This is particularly true for Northwest
BC, which is being rapidly developed and likely contains many of the last remaining
populations of wild, healthy CCT populations.
My research examined seasonal behaviours of CCT at a scale and scope that had not
been completed previously. However, additional research is required to substantiate these
findings. Given the metapopulation structure of CCT populations and the seemingly flexible
migratory behaviours they exhibit, behaviours should be expected to vary among
populations (Wenburg and Bentzen 2001, Costello 2006, Johnson et al. 2010). Thus, our
understanding of CCT and factors shaping the subspecies behaviours will improve as more
studies are conducted throughout the subspecies’ range. Specific recommendations for
future research were presented in the discussions of chapters 1 and 2. It is recommended,
however, that future studies examining CCT behaviours focus upon life history events as
they are most likely to be synchronized, structured and therefore predictable.
116

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139

APPENDICES
Chapter 1 Appendix
Table A1.1. Physical characteristics of all male and female CCT sampled during angling.
n

mean

Age (y)
SE
range

Fork Length (mm)
mean
SE
range

mean

Weight (g)
SE
range

Male 80
Female 144

3.6
3.9

0.11
0.11

319
335

414
500

23.53
24.71

2- 6
2- 7

7.32
6.18

135 - 455
110 - 480

Condition Factor (k)*
mean
SE
range

35 - 1020 1.13
45 - 1180 1.13

0.04
0.03

0.84 - 1.67
0.74 - 1.98

Welch's two sample t: t(173.79) = -2.33, p = 0.021 t(181.05) = -1.63, p = 0.10 t(198.28) = -2.54, p = 0.012 t(370.0) = -0.048, p = 0.96

140

A

B

C

D

Figure A1.1. Fork length (A), weight (B), age (C) and condition factor (D) of all CCT sampled during angling.

141

Table A1.2. Summary of the physical characteristics of male and female CCT radio tagged with large transmitters in year 1 and year 2. Significant test results are
presented in bold.

Year
Combined

Sex
Male
Female

n
31
62

Welch's two sample t:
1

Male
Female

14
26

Welch's two sample t:
2

Male
Female

17
36

Welch's two sample t:
1
2

Combined

40
53

Welch's two sample t:
1
2

Male

14
17

Welch's two sample t:
1
2

Female

Welch's two sample t:

26
36

Age (y)
Mean SE
Range
3.9 0.15
3- 6
4.5 0.14
3- 7

Fork Length (mm)
Mean SE
Range
377
5.6
331 - 455
390
5.4
330 - 480

Weight (g)
Mean SE
Range
605 23.4 440 - 1020
703 29.3 430 - 1180

Condition Factor (g/cm3)
Mean SE
Range
1.13 0.02
0.92 - 1.45
1.15 0.01
0.93 - 1.37

t(67.1) = -2.59, p = 0.01

t(78.8) = -1.70, p = 0.09

t(89.5) = -2.59, p = 0.01

t(45.7) = -0.88, p = 0.38

4.2
5.0

401
413

674
819

0.26
0.25

3- 6
3- 7

6.8
8.3

367 - 455
330 - 480

36.9
45.9

520 - 1020
440 - 1180

t(25.4) = -2.25, p = 0.03

t(37.3) = -1.12, p = 0.27

t(37.6) = -2.45, p = 0.02

3.8
4.2

357
373

557
618

0.18
0.15

3- 5
3- 6

4.5
5.9

331 - 392
330 - 446

23.1
31.9

440 - 720
430 - 1020

t(35.5) = -1.66, p = 0.11

t(50.3) = -2.25, p = 0.03

t(50.9) = -1.80, p = 0.08

4.6
4.0

409
368

768
596

0.21
0.12

2- 7
3- 6

5.9
4.4

330 - 480
330 - 446

34.0
23.2

440 - 1180
430 - 1020

t(49.9) = 2.61, p = 0.01

t(76.4) = 5.57, p < 0.001

t(71.9) = 4.18, p < 0.001

4.2
3.8

401
357

674
557

0.26
0.18

3- 6
3- 5

6.8
4.5

367 - 455
331 - 392

36.9
23.1

520 - 1020
440 - 720

t(31.7) = 2.92, p = 0.01

t(48.1) = 3.91, p < 0.001

t(47.1) = 3.57, p < 0.001

5.0
4.2

413
373

819
618

0.25
0.15

3- 7
3- 6

t(25.7) = -5.2, p < 0.001

8.3
5.9

330 - 480
330 - 446

t(22.2) = 2.91, p = 0.01

45.9
31.9

440 - 1180
430 - 1020

t(19.1) = 1.3, p = 0.21

1.03
1.13

0.02
0.02

0.92 - 1.10
0.94 - 1.34

t(34.85) = -4.05, p < 0.001
1.20
1.17

0.03
0.02

1.06 - 1.45
1.03 - 1.37

t(25.7) = 1.32, p = 0.20
1.09
1.18

0.02
0.02

0.92 - 1.34
1.03 - 1.39

t(86.6) = -3.88, p < 0.001
1.03
1.20

0.02
0.03

0.92 - 1.10
1.06 - 1.45

t(25.7) = -5.20, p <0.001
1.13
1.17

0.02
0.02

0.94 - 1.34
1.03 - 1.37

t(54.4) = -1.26, p = 0.21

142

Table A1.3. Physical characteristics, capture summary and fate of all CCT selected for radio tagging in year 1.
ID Sex Age FL (mm)

Capture
Final
Date
Relocation

1
2
3
6
7
8
9
10
12
13
15
19
21
29
34
43
44
45
47
49
50
51
52
53
54
67
69
74
77
87
88
91
92
93
94
95
96
97
99
100
102

8-Aug-12 21-Oct-13
Yes
No upstream movement observed after 6-Sept-2013.
10-Aug-12 10-Dec-13
Yes
Fish still alive on 10-Dec-2013 when tag expired.
11-Aug-12 17-Dec-12
Yes
Recaptured on 16-Nov-2012. Not observed after 20-Dec-2012
22-Aug-12 20-Nov-12
No
No upstream movement after capture.
22-Aug-12 30-Oct-12 Unknown*** No upstream movement after moving into Goose OW area.
22-Aug-12 12-Aug-13 Unknown** Insufficient relocation data. Relocated during 1 aerial tracking flight.
23-Aug-12 4-Feb-14
Yes
Fish alive when tag expired on 4-Feb-2014. CCT returned to OW habitat used in first winter.
23-Aug-12 23-Sep-12
No
No upstream movement after capture.
26-Aug-12 1-Feb-13
Yes
No upstream movement observed after moving into Wedeene OW area on 17-Dec-2012.
31-Aug-12 4-Feb-14
Yes
Survived spawn. Estuary from 23-May to 1-July. Returned to Goose OW. Tag expired after 4-Feb-2014.
1-Sep-12 28-Oct-12
No
No upstream movement observed after tagging.
12-Sep-12 17-May-13
Yes
Chicken Ck. spawning mort. Recovered on 17-May-2013.
15-Sep-12 8-Mar-13
Yes
Not observed after 8-March-2013 at 16.5 rKM.
17-Sep-12 22-Apr-13
Yes
Goose Ck. spawning mort. Recovered on 22-Apr-2013.
23-Sep-12 1-May-13
Yes
Upper Big Wedeene spawning mort. No upstream movement after 1-May-2013.
26-Sep-12 27-Apr-13
Yes
Cecil Ck. spawning mort. No movement after 27-April-2013.
26-Sep-12 17-May-13
Yes
Chicken Ck. spawning mort. Recovered on 17-May-2013.
26-Sep-12 1-May-13
Yes
Big Wedeene spawning mort. No movement after 1-May-2013
6-Oct-12 10-Mar-14
Yes
Survived spawn. In estuary from 26-May-2013 to 11-July-2013. Tag expired after 4-Feb-2014.
8-Oct-12 6-Sep-13
Yes
Survived spawn. Moved to estuary on 23-May-2013, predated on by eagle before 6-Sept-2013.
8-Oct-12 4-Feb-14
Yes
Survived spawn. Tag expired after 4-Feb-2014.
28-Oct-12 5-Apr-13
Yes
No upstream movement observed after 31-March-2013. Tag recovered on 23-April-2013.
2-Nov-12 28-Mar-14
Yes
Survived spawn. In estuary from 3-June to 30-July. No upstream movement after 15-Jan-2014.
2-Nov-12 25-Feb-13
Yes
No upstream movement observed after 25-Feb-2013.
3-Nov-12 9-Dec-12 Unknown** Not observed during any aerial relocation flights.
7-Nov-12 6-Apr-13
Yes
Killed by angler on 6-April-2013.
8-Nov-12 21-Oct-13
Yes
Survived spawn. In estuary 20-May to 13-Aug-2013. No upstream movement after 21-Oct-2013.
10-Nov-12 13-May-13
Yes
Predated upon by eagle on 13-May-2013. Tag expired 5-May-2014.
16-Nov-12 21-Mar-14
Yes
Survived spawn. In estuary 22-May to 23-July-2013. Mortality between 23-July and 10-Dec-2013.
19-Nov-12 17-Dec-13
No
No upstream movement observed after tagging.
19-Nov-12 27-Apr-13
Yes
Chicken Ck. spawning mort after 27-April-2013.
24-Nov-12 28-Apr-14
Yes
Survived spawn. Overwintered in Wedeene OW area. Tag expired on 28-April-2014.
24-Nov-12 24-May-13
Yes
Big Wedeene spawner. Not observed after 24-May-2013.
10-Dec-12 14-Apr-13
Yes
KTR Trib spawning mort. No upstream movement after 14-April-2013.
11-Dec-12 1-May-14
Yes
Little Wedeene spawning mort - after 1-May-2013.
11-Dec-12 1-May-13
Yes
Predated upon by eagle between 27-April and 1-May-2013.
12-Dec-12 6-May-13
Yes
Cecil Ck. spawning mort. No upstream movement after 14-April-2013. Recovered on 6-May-13.
12-Dec-12 27-Apr-13
Yes
Deception Ck. spawning mort. No upstream movement after 27-April-2013. Recovered on 3-May-2013.
12-Dec-12 6-May-13
Yes
McNeil Ck. spawning mort. No upstream movement after 6-May-2013. Recovered on 17-May-2013.
12-Dec-12 17-Apr-13
Yes
Survived spawn and second winter. Estuary28-May to 17-July-2013. Tag expired on 17-April-2014.
15-Dec-12 1-Feb-13
No
No upstream movement observed after tagging.

M
F
F
F
F
F
F
M
F
F
M
M
F
M
M
F
F
F
F
F
F
F
F
F
F
F
F
M
F
F
M
F
M
F
F
M
M
M
M
M
F

4
3
5
4
4
6
6
4
4
4
4
6
4
7
5
6
7
5
4
5
5
5
6
4
4
5
3
5
3
4
4
6

398
340
330
345
370
435
385
375
435
455
417
455
380
435
432
423
400
404
450
414
460
438
419
348
465
480
384
380
409
408
404
424
396
447
454
367
399
376
398
384
448

Survived
Tagging?

Comments

Unknown* = Fish moved directly out of system following tagging.
Unknown** = Fish not relocated sufficiently to determine fate.
Unknown*** = Fish not observed departing from OW habitat occuppied within 6 weeks of tagging.

143

Table A1.4. Physical characteristics, capture summary and fate of all CCT selected for radio tagging in year 2.
Fish ID Sex Age FL (mm)

Capture
Final
Date
Relocation

118
123
132
134
141
143
146
147
148
149
151
152
154
155
156
157
158
159
161
162
163
166
169
170
171
172
173
174
175
176
177
179
180
181
182
185
187
189
195
200
206
207
208
209
211
212
217
218
220
222
224
225
227
231
232
233
234
235
236
240
241
242
245
249
250
251
252
255

20-Jun-13 6-Sep-13
Yes
Last observed on 6-Sept-2013 at 11.2 rKM. Possibly captured.
9-Jul-13 13-May-14
Yes
Duck Ck. spawning mort. No upstream movement after 5-May-2014. Recovered on 13-May-2014.
13-Jul-13 16-Dec-13
Yes
Last moving past receiver at 2.2 rKM on 6-Sept-2013.
14-Jul-13 28-Jun-14
Yes
Survived spawn (Cecil Ck.), in estuary from 3-June to 28-June-2014. Not observed after 28-June-2014
18-Jul-13 22-Nov-13
No
No movement observed after tagging.
21-Jul-13 21-Oct-13
No
No upstream movement observed after tagging.
21-Jul-13 TAGGING
No
Did not survive surgery.
21-Jul-13 18-Sep-13
Yes
Last observed on 18-Sept-2013 at 16.5 rKM. Possibly captured.
21-Jul-13 27-May-14
Yes
Survived spawn (Chicken Ck.), last observed 15-May-2014 in Hirsch Ck.
22-Jul-13 TAGGING
No
Did not survive surgery.
25-Jul-13 27-May-14
Yes
Spawned (Nalbeelah Ck.), last observed near mouth of Nalbeelah, 29-May-2014.
23-Jul-13 10-May-14
Yes
Cecil Ck. spawning mort between 11-April and 5-May-2014. Recovered on 10-May-13.
23-Jul-13 9-Sep-13 Unknown* Last observed moving out of system on 9-Sept-2013.
25-Jul-13 25-Jul-13 Unknown** Not observed after tagging.
25-Jul-13 16-May-14
Yes
Powerline Ck. spawning mort. No upstream movement after 9-May-2014.
25-Jul-13 27-May-14
Yes
Survived spawn (McKay Ck.). Not observed after 27-May-2014.
25-Jul-13 9-May-14
Yes
Nalbeelah Ck. spawning mort.No upstream movement after 9-May-2014.
29-Jul-13 18-Jul-14
Yes
Survived spawn (McNeil Ck.), in estuary 1-June to 18-July-2014. Not observed after 18-July-2014.
12-Aug-13 21-Oct-13
No
No upstream movement after 6-Sept-2013. Not observed after 22-Nov-2013.
12-Aug-13 13-Jul-14
Yes
Survived spawn (Upper Kitimat), in estuary 1-June to 13-July-2014. Not observed after 13-July-2014.
12-Aug-13 4-Feb-14
Yes
Not observed after 4-Feb-2014. Likely captured near 19.6 rKM.
15-Aug-13 21-Aug-13
No
No upstream movement after tagging.
17-Aug-13 25-Aug-13 Unknown* Last observed moving out of system on 25-Aug-2013 at 8.3 rKM.
17-Aug-13 13-Apr-14 Unknown* Last observed moving out of system on 20-Aug-2013 at 8.3 rKM.
17-Aug-13 4-Feb-14
No
No upstream movement after tagging.
17-Aug-13 TAGGING
No
Did not survive surgery.
18-Aug-13 4-Sep-13
No
No upstream movement after tagging.
18-Aug-13 30-Aug-13 Unknown* Last observed moving out of system on 30-Aug-2013 at 8.3 rKM.
18-Aug-13 6-Sep-13 Unknown* Last observed moving out of system on 6-Sept-2013.
18-Aug-13 10-Feb-14 Unknown** Not observed after 6-Sept-2013.
18-Aug-13 6-Sep-13
No
No upstream movement after tagging.
21-Aug-13 11-Sep-13 Unknown** Not observed after 11-Sept-2013.
21-Aug-13 6-Feb-14 Unknown** Not observed during any aerial relocation flights.
5-Sep-13 8-Sep-13
No
No upstream movement after tagging.
9-Sep-13 10-Dec-13 Unknown*** No upstream movement observed after entering Goose overwinter area on 10-Dec-2013.
9-Sep-13 3-May-14
Yes
Powerline Ck. spawning mort. No upstream movement after 3-May-2014.
13-Sep-13 22-Nov-13 Unknown*** No upstream movement after 22-Nov-2013.
15-Sep-13 27-Sep-13 Unknown* Last observed on 27-Sept-2013 at 2.2 rKM moving out of system.
17-Sep-13 10-Dec-13
Yes
Moved continuously downstream after tagging, last observed in system on 10-Dec-2013.
18-Sep-13 8-Oct-13
No
No upstream movement after tagging.
21-Sep-13 10-Dec-13
No
No upstream movement after tagging.
24-Sep-13 28-Mar-14
Yes
Not observed in spawning habitat. Last relocated on 28-March-2014.
24-Sep-13 5-May-14
Yes
Cecil Ck. spawning mort. No upstream movement after 5-May-2014. Tag recovere on 15-May-2014.
25-Sep-13 27-May-14
Yes
Survived spawn (Cecil Ck.), last observed 27-May-2014 entering estuary.
25-Sep-13 27-May-14
Yes
Big Wedeene spawner. Fate unclear. Last observed 27-May-2014.
25-Sep-13 27-May-14
Yes
Survived spawn (Nalbeelah Ck.). Last observed on 27-May-2014.
26-Sep-13 29-Apr-14
Yes
Goose Ck. spawning mort. Recovered on 29-April-2014.
26-Sep-13 14-Jul-14
Yes
Survived spawn (Chicken Ck.), in estuary 8-June to 14-July-2014.
27-Sep-13 15-Jan-14
Yes
Moved continuously downstream after tagging, no movement after 21-March-2014.
28-Sep-13 15-Jan-14
Yes
Last observed on 7-April-2014 in Goose Pool OW area
29-Sep-13 11-Apr-14
Yes
Predated upon by eagle between 2-April-2014 and 11-April-2014.
7-Oct-13 5-May-14
Yes
Duck Ck. spawning mort. No upstream movement after 5-May-2014. Tag recovered 6-May-2014.
7-Oct-13 29-May-14
Yes
Fate unclear. No upstream movement observed after 11-April-2014. Fish may have moved to estuary on 29-May-2014.
9-Oct-13 21-Oct-13 Unknown** Not observed after 21-Oct-2013.
9-Oct-13 30-Jun-14
Yes
Survived spawn (upper Kitimat), in estuary 22-May to 30-June-2014. Last observed 30-June-2014.
9-Oct-13 10-Dec-13
No
Fish moved continuously downstream after tagging.
9-Oct-13 4-Mar-14
Yes
Last observed on 4-March-2014 in McNeil Ck. No upstream movement after 15-Jan-2014.
9-Oct-13 9-Oct-13 Unknown** Not observed after tagging.
9-Oct-13 14-May-14
Yes
Not observed in spawning habitat but likely spawned near Airpark. Last observed moving into estuary 14-May-2014.
10-Oct-13 30-Mar-14
Yes
Last observed on 30-March-2014 at 16.5 rKM
10-Oct-13 24-May-14
Yes
Survived spawn (Big Wedeene), last observed moving into estuary on 24-May-2014.
10-Oct-13 27-May-14
Yes
Not observed in spawning habitat. Last relocated on 27-May-2014.
11-Oct-13 4-Feb-14
Yes
No upstream movement observed after 4-Feb-2014.
14-Oct-13 27-May-14
Yes
Big Wedeene spawning mort. No upstream movement after 9-May-2014.
14-Oct-13 15-Jan-14
Yes
Not observed departing Cable Car OW area. No movement after 15-Jan-2014.
15-Oct-13 19-Jun-14
Yes
Survived spawn (Little Wedeene), in estuary from 1-June to 19-June-2014.
15-Oct-13 4-Mar-14
Yes
Not observed leaving Goose overwintering area. No movement after 4-March-2014.
18-Oct-13 17-Apr-14
Yes
Deception Ck. spawning mort. No upstream movement after 28-April-2014.

M
M
M
F
F
F
M
F
F
F
F
F
F
F
F
F
F
F
F
F
F
M
M
F
F
M
M
F
M
F
F
F
F
F
M
F
M
F
F
F
M
F
F
M
F
F
F
F
F
M
F
F
M
M
M
F
F
M
F
F
F
M
M
M
F
M

5
5
3
5
4
4
5
4
4
4
5
5
3
4
6
5
3
5
4
3
3
3
3
3
3
3
3
4
3
3
3
5
5
3
5
4
3
3
3
4
5
4
5
4
4
4
5
4
4
4
4
4
5
5
4
4
5
4
4
4
3
4
4
4

380
363
342
435
388
369
390
392
389
391
338
418
350
297
349
440
371
446
336
388
333
387
287
346
333
338
335
335
341
350
293
283
276
359
399
435
345
338
340
344
366
332
392
436
364
331
374
372
346
344
430
368
353
365
416
355
320
380
350
345
376
357
330
371
357
358
335
355

Survived
Tagging?

Comments

Unknown* = Fish moved directly out of system following tagging.
Unknown** = Fish not relocated sufficiently to determine fate.
Unknown*** = Fish not observed departing from OW habitat occuppied within 6 weeks of tagging.

144

Table A1.5. Summary of the behaviours of CCT tracked into overwintering habitats in year 1 and 2.

Fish #

Sex

Age (y) FL (mm)

Summary of winter movement behaviours

#002

F

-

340

Mobile, captured in Nalbeelah. Overwintered near Airpark, Deception and
Cecil in first winter. Spawned in McNeil and then returned to Nalbeelah area.
In second winter, was first relocated near Cecil Ck. on 22-Nov-2013. Tag
expired on 10-Dec-2013.

#009

F

4

385

Stationary in both winters, occupied same overwintering area during both
winters. Occupied overwintering area from 20-Nov-2012 to during the first
winter. Spawned and then went to estuary. Returned to initial overwintering
area and occupied it from 22-Nov-2013 to 4-Feb-2014 during the second
winter. Suspect that tag expired while still in overwintering area.

#013

F

6

455

Stationary in both winters, occupied same overwintering area during both
winters. Captured near initial overwintering area on 31-Aug-2013 and
remained until 9-April-2013. Spawned in spring and then moved into estuary.
Relocated in initial overwintering area on 21-Oct-2013. Final relocation was
on 4-Feb-2014, while still in overwintering area.

#050

F

7

460

Stationary in both winters, occupied different overwintering areas in first
and second winter. In first winter, CCT remained in initial overwintering area
(Deception) from 20-Nov-2012 to 28-March-2013. CCT spawned in the Big
Wedeene and then moved throughout watershed during summer/fall.
During the second winter it was relocated in a new overwintering area
(mouth of Wedeene) on 21-Oct-2013. Tag expired after 4-Feb-2014, fish may
have died previously.

#052

F

5

419

Stationary in 2012, mobile in 2013. Overwintered in upper Big Wedeene from
2-Nov-2012 to 14-April-2013. Spawned (19-April-2013) and then moved
downstream to the estuary. Relocated in lower Big Wedeene (22-Nov-2013 to
10-Dec-2013) and then moved into the Big Wedeene side channel until tag
expired on 28-March-2014.

#091

F

6

424

Captured in upper watershed and primarily overwintered near Cecil Ck in
first winter. Spawned (Chist Ck.) and remained in upper watershed through
summer. Overwintered in Clay Banks side channel through second winter.
Last relocated on 28-April-2014, may have died previously.

145

Table A1.6. Physical characteristics of stationary and mobile CCT radio tagged with large transmitters in year 1 and year 2. Significant tests results are bold.

Year
Winter Behaviour
Combined
Stationary
Mobile

n
23
34

Welch's two sample t:
1

Stationary
Mobile

Stationary
Mobile

18
12

5
22

Welch's two sample t:
1
2

Combined

Stationary

30
27

18
5

Welch's two sample t:
1
2

Mobile

Welch's two sample t:

4.8
4.4

0.30
0.38

3- 7
3- 7

Weight (g)
Mean
SE
Range
833
41.1 540 - 1180
659
34.1 430 - 1050

Condition Factor (g/cm3)
Mean
SE
Range
1.13
0.02 0.92 - 1.38
1.13
0.02 0.93 - 1.37

t(110.7) = 5.07, p < 0.001

t(97.6) = 4.67, p < 0.001

t(90.2) = 0.05, p = 0.96

419
407

826
734

6.6
11.3

376 - 460
340 - 480

t(18.5) = 0.91, p = 0.38

4.8
4.3

411
373

0.37
0.14

4- 6
3- 5

4.7
4.4

0.23
0.14

3- 7
3- 6

16.2
7.3

368 - 440
330 - 446

t(5.7) = 2.14, p = 0.08
414
380

6.0
7.1

340 - 480
330 - 446

48.0
60.8

540 - 1180
440 - 1050

t(23.1) = 1.18, p = 0.25
862
618

85.5
39.3

620 - 1020
430 - 1000

t(5.8) = 2.60, p = 0.04
789
663

37.9
39.6

440 - 1180
430 - 1020

1.11
1.07

0.02
0.02

0.92 - 1.25
0.93 - 1.18

t(26.8) = 1.19, p = 0.24
1.23
1.17

0.04
0.02

1.17 - 1.38
1.03 - 1.37

t(6.0) = 1.49, p = 0.19
1.09
1.18

0.02
0.02

0.92 - 1.25
1.03 - 1.38

t(36.5) = 1.08, p = 0.29

t(52.4) = 3.68, p < 0.001

t(54.5) = 2.30, p = 0.03

t(54.4) = -3.72, p < 0.001

4.8
4.8

419
411

826
862

1.11
1.23

0.30
0.37

3- 7
4- 6

t(9.6) = -0.03, p = 0.98
12
22

Fork Length (mm)
Mean
SE
Range
417
6.1
368 - 460
385
6.7
330 - 480

t(17.1) = 0.71, p = 0.49

t(5.2) = 1.37, p = 0.23

Welch's two sample t:
1
2

Range
3- 7
3- 7

t(66) = 2.45, p = 0.02

Welch's two sample t:
2

Mean
4.8
4.3

Age (y)
SE
0.2
0.1

4.44
4.25

0.38
0.14

3- 7
3- 5

t(10.4) = 0.48, p = 0.64

6.6
16.2

376 - 460
368 - 440

t(5.4) = 0.46, p = 0.67
407
373

11.3
7.3

340 - 480
330 - 446

t(20.2) = 2.55, p = 0.02

48.0
85.5

540 - 1180
620 - 1020

t(6.8) = -0.37, p = 0.72
734
618

60.8
39.3

440 - 1050
430 - 1000

t(20.3) = 1.61, p = 0.12

0.02
0.04

0.92 - 1.25
1.17 - 1.38

t(7.0) = -2.79, p = 0.03
1.07
1.17

0.02
0.02

0.93 - 1.18
1.03 - 1.37

t(25.2) = -3.4, p = 0.002

146

Table A1.7. River position (km) of initial and final overwintering habitats used by male and female CCT in year
1 and 2. Significant tests results are presented in bold.
Year

Sex

Combined

Male
Female

n

Initial OW Position
Mean SD
Range

n

Final OW Position
Mean SE
Range

Welch's two sample t:
Initial vs Final

22
47

24.4
24.5

20
32

24.0
24.2

t(54.6) = -0.19, p = 0.85
t(105.8) = 0.31, p = 0.76

Welch's two sample t:
1

Male
Female

Male
Female

12
19

Combined

10
29

Male

31
37

Female

Welch's two sample t:

10.8 to 36.9
10.8 to 35.7

12
16

22.7
24.7

2.5
1.5

10.8 to 34.6
10.8 to 37.1

24.9
24.1

1.5
1.3

10.8 to 36.9
10.8 to 37.1

12
10

25.8
22.7

2.3
2.5

10.8 to 36.9
10.8 to 34.6

8
15

24.4
24.7

2.0
1.5

10.8 to 35.7
10.8 to 37.1

t(31.6) = -0.03, p = 0.98

2.2 10.8 to 32.1
2.4 10.8 to 35.7

23.3
24.0

3.1 10.8 to 31.9
1.8 11 to 33.5

t(4.0) = -0.36, p = 0.74
28
24

24.3
24.0

1.7 10.8 to 35.7
1.5 10.8 to 33.5

t(56.8) = -0.16, p = 0.87
12
8

t(19.6) = 0.71, p = 0.49
19
29

24.4
24.1

t(17.6) = -0.2, p = 0.84

t(73.6) = 0.05, p = 0.62

Welch's two sample t:
1
2

2.3
2.0

t(14.6) = -0.81, p = 0.43

Welch's two sample t:
1
2

25.8
24.4

1.8 10.8 to 32.1
1.5 10.8 to 35.7

t(49.3) = -0.03, p = 0.97

t(25.6) = 0.05, p = 0.96

Welch's two sample t:
1
2

10.8 to 36.9
10.8 to 37.1

t(53.3) = -0.51, p = 0.61

Welch's two sample t:
2

1.7
1.2

16
15

24.4
23.3

2.2 10.8 to 32.1
3.1 10.8 to 31.9

t(16.5) = 0.65, p = 0.53
t(22.0) = 0.46, p = 0.65
t(5.7) = -0.21, p = 0.84
t(25.2) = -0.09, p = 0.93
t(60.3) = 0.54, p = 0.59
t(70.1) = -0.00, p = 0.99
-

t(6.5 = -0.20, p = 0.85

-

24.1
24.0

-

2.4 10.8 to 35.7
1.8 11 to 33.5

t(18.2) = -0.57, p = 0.58

-

147

Table A1.8. River position of initial and final overwintering habitats used by mobile and stationary CCT in year
1 and 2. Significant tests results are presented in bold.
Year

Winter Behaviour

Combined

Stationary
Mobile

n

Initial OW Position
Mean SD
Range

n

Final OW Position
Mean
SE

25
40

23.7
25.1

25
27

23.7
24.5

Welch's two sample t:
1
2

Combined

t(36.2) = -0.33, p = 0.74
30
34

Welch's two sample t:
1

Stationary
Mobile

Stationary
Mobile

Stationary

6
30

Mobile
Welch's two sample t:

24.0
27.4

2.2 10.8 to 35.7
1.7 15.7 to 36.9

22.8
24.3

3.9 10.8 to 33.5
1.3 10.8 to 37.1

19
6

24.0
22.8

2.2 10.8 to 35.7
3.9 10.8 to 33.5

24.3
24.0

27.4
24.3

1.7 15.7 to 36.9
1.3 10.8 to 37.1

t(26.6) = 0.83, p = 0.41

10.8 to 35.7
10.8 to 32

t(43.7) = 0.76, p = 0.45
t(110.3) = -0.2, p = 0.84

1.7
1.5

10.8 to 35.7
10.8 to 33.5

t(64.8) = 0.52, p = 0.6
t(66.2) = -0.36, p = 0.72

t(60.7) = -0.46, p = 0.65
19
9

24.0
24.9

2.2
2.5

10.8 to 35.7
10.8 to 30.7

t(21) = -0.23, p = 0.82

t(21) = -1.85, p = 0.08
6
17

22.8
24.1

3.9
1.7

10.8 to 33.5
10.8 to 32

t(33.4) = -0.08, p = 0.94

2.2
3.9

10.8 to 35.7
10.8 to 33.5

-

2.5
1.7

10.8 to 30.7
10.8 to 32

-

19
6

24.0
22.8

t(8.8) = 0.31, p = 0.77
11
30

1.9
1.3

Welch's two sample t:
Initial vs Final

t(31.4) = -1.33, p = 0.19
28
24

t(6.2) = -0.33, p = 0.75

Welch's two sample t:
1
2

1.5 10.8 to 36.9
1.3 10.8 to 37.1

t(26.1) = -0.61, p = 0.55

Welch's two sample t:
1
2

25.2
24.0

t(77.6) = 0.44, p = 0.66
19
11

Welch's two sample t:
2

1.9 10.8 to 35.7
1.1 10.8 to 37.1

Range

9
17

24.9
24.1

t(21.9) = 0.89, p = 0.39

-

148

Table A1.9. Median date male and female CCT arrived in, and were captured in, initial overwintering habitats in year 1 and year 2. Note that 1 CCT captured in
an overwintering habitat in year 1 was excluded from this analysis (Fish#003). Significant tests results are bold.
Year

Sex

Combined

Male
Female

n

Observed in Overwintering Habitats
Median
SD
Range

n

Captured in Overwintering Habitats
Median
SD
Range

n

NOT Captured in Overwintering Habitats
Median
SD
Range

22
46

20-Nov
21-Oct

11
15

19-Nov
21-Oct

11
31

20-Nov
30-Oct

Two Sample KS Test
1

Male
Female

Male
Female

12
19

Combined

10
27

Male

31
37

Female

Two Sample KS Test

12-Sep to 17-Dec
11-Aug to 17-Dec

7
7

21-Oct
21-Oct

18.5
18.6

24-Sep to 22-Nov
06-Sep to 22-Nov

20-Nov
21-Oct

27.2
18.3

11-Aug to 17-Dec
11-Aug to 17-Dec

12
10

22-Nov
21-Oct

26.0
18.5

12-Sep to 17-Dec
24-Sep to 22-Nov

4
8

20-Nov
21-Oct

27.7
18.6

11-Aug to 17-Dec
06-Sep to 22-Nov

Ho: 2012 > 2013; d = 0.71, p < 0.001

11-Dec
8-Nov

33.7
41.2

12-Sep to 17-Dec
11-Aug to 11-Dec

10-Oct
21-Oct

9.4
14.7

24-Sep to 14-Oct
09-Sep to 21-Oct

14
12

22-Nov
14-Oct

37.4
13.1

11-Aug to 17-Dec
09-Sep to 21-Oct

5
12

11-Dec
10-Oct

33.7
9.4

12-Sep to 17-Dec
24-Sep to 14-Oct

6
19

8-Nov
21-Oct

41.2
14.7

11-Aug to 11-Dec
09-Sep to 21-Oct

Ho: 2012 > 2013; d = 0.86, p = 0.004

20-Nov
20-Nov

12.1
16.7

20-Nov to 17-Dec
06-Oct to 17-Dec

23-Oct
21-Oct

16.1
18.9

21-Oct to 22-Nov
06-Sep to 22-Nov

Ho: Male > Female; d = 0.24, p = 0.601
11
31

20-Nov
30-Oct

16.6
18.1

21-Oct to 17-Dec
06-Sep to 17-Dec

Ho: 2012 > 2013; d = 0.66, p < 0.001
5
6

Ho: 2012 > 2013; d = 0.86, p = 0.023
7
8

21-Oct to 17-Dec
06-Sep to 17-Dec

Ho: Male > Female; d = 0.25, p = 0.639

Ho: 2012 > 2013; d = 0.85, p < 0.001
7
4

18.6
20.5

Ho: Male > Female; d = 0.21, p = 0.477

Ho: Male < Female; d = 0.75, p = 0.050

Ho: 2012 > 2013; d = 0.72, p = 0.004
19
27

12-Sep to 17-Dec
11-Aug to 11-Dec

Ho: Male > Female; d = 0.43, p = 0.280

Ho: 2012 > 2013; d = 0.71, p < 0.001

Two Sample KS Test
1
2

26.0
27.7

Ho: Male < Female; d = 0.29 p = 0.301

Two Sample KS Test
1
2

22-Nov
20-Nov

35.8
31.2

Ho: Male > Female; d = 0.35, p = 0.221

Ho: Male > Female; d = 0.34, p = 0.182

Two Sample KS Test
1
2

12-Sep to 17-Dec
11-Aug to 17-Dec

Ho: Male > Female; d = 0.22, p = 0.233

Two Sample KS Test
2

28.0
24.7

20-Nov
23-Oct

12.1
16.1

20-Nov to 17-Dec
21-Oct to 22-Nov

Ho: 2012 > 2013; d = 0.67, p = 0.089
12
19

20-Nov
21-Oct

16.7
18.9

06-Oct to 17-Dec
06-Sep to 22-Nov

Ho: 2012 > 2013; d = 0.65, p =0.002

149

Table A1.10. Median date mobile and stationary CCT arrived in, and were captured in, initial overwintering habitats in year 1 and year 2. Note that 1 CCT
captured in an overwintering habitat in year 1 was excluded from this analysis (Fish#003). Significant tests results are presented in bold.
Year
1
2

Winter
Behaviour
Combined

n

Observed in Overwintering Habitats
Median
SD
Range

n

Captured in Overwintering Habitats
Median
SD
Range

n

30
34

20-Nov
21-Oct

13
12

22-Nov
14-Oct

17
22

Two Sample KS Test
1

Stationary
Mobile

Two sample KS Test:
2

Stationary
Mobile

Two sample KS Test:
1
2

Combined

Stationary

18
12

Mobile

Two sample KS Test:

20-Nov
20-Nov

22.7
18.0

12-Sep to 17-Dec
06-Oct to 12-Dec

6
28

21-Oct
21-Oct

24.0
17.3

09-Sep to 22-Nov
06-Sep to 22-Nov

7
6

20-Nov
21-Oct

20.6
18.4

11-Aug to 17-Dec
06-Sep to 22-Nov

20-Nov
2-Dec

2
10

20-Nov
21-Oct

22.7
24.0

12-Sep to 17-Dec
09-Sep to 22-Nov

13
12

20-Nov
21-Oct

18.0
17.3

06-Oct to 12-Dec
06-Sep to 22-Nov

Ho: 2012 > 2013; d = 0.74, p < 0.001

12-Sep to 17-Dec
07-Nov to 12-Dec

11
6

23-Sep
18-Oct

19.8
8.7

09-Sep to 07-Oct
24-Sep to 21-Oct

22-Nov
14-Oct

26.4
13.1

11-Aug to 17-Dec
09-Sep to 21-Oct

7
2

20-Nov
23-Sep

33.5
19.8

12-Sep to 17-Dec
09-Sep to 07-Oct

4
18

2-Dec
18-Oct

14.6
8.7

07-Nov to 12-Dec
24-Sep to 21-Oct

Ho: 2012 > 2013; d = 1.0, p < 0.001

06-Oct to 17-Dec
06-Sep to 22-Nov

20-Nov
20-Nov

13.5
18.4

30-Oct to 17-Dec
06-Oct to 20-Nov

21-Oct
21-Oct

16.0
19.4

21-Oct to 22-Nov
06-Sep to 22-Nov

Ho: Stationary < Mobile; d = 0.083, p = 0.960
17
22

20-Nov
21-Oct

15.6
16.5

06-Oct to 17-Dec
06-Sep to 22-Nov

Ho: 2012 > 2013; d = 0.66, p < 0.001
11
4

Ho: 2012 > 2013; d = 0.86, p = 0.102
6
10

15.6
16.5

Ho: Stationary > Mobile; d = 0.18, p = 0.770

Ho: 2012 > 2013; d = 0.86, p < 0.001

Ho: 2012 > 2013; d = 0.78, p = 0.004
12
28

33.5
14.6

20-Nov
21-Oct

Ho: 2012 > 2013; d = 0.66, p < 0.001

Ho: Stationary < Mobile; d = 0.80, p = 0.118

Ho: 2012 > 2013; d = 0.71, p < 0.001
18
6

11-Aug to 17-Dec
09-Sep to 21-Oct

Ho: Stationary < Mobile; d = 0.29, p = 0.588

Ho: Stationary < Mobile; d = 0.23, p = 0.597
30
34

26.4
13.1

Ho: 2012 > 2013; d = 0.86, p < 0.001

Ho: Stationary > Mobile; d = 0.17, p = 0.665

Two sample KS Test:
1
2

11-Aug to 17-Dec
06-Sep to 22-Nov

Ho: 2012 > 2013; d = 0.71, p < 0.001

Two Sample KS Test
1
2

20.6
18.4

NOT Captured in Overwintering Habitats
Median
SD
Range

20-Nov
21-Oct

13.5
16.0

30-Oct to 17-Dec
21-Oct to 22-Nov

Ho: 2012 > 2013; d = 0.75, p = 0.037
6
18

20-Nov
21-Oct

18.4
19.4

06-Oct to 20-Nov
06-Sep to 22-Nov

Ho: 2012 > 2013; d = 0.56, p = 0.062

150

Table A1.11. Absolute distance male and female CCT travelled to initial overwintering areas. Note that CCT captured within overwintering areas have been
excluded. Summary includes distance travelled in mainstem (rkm), tributaries (tkm) and in total (rkm + tkm).

Year

Sex

Combined

Male
Female

Absolute Distance (rkm)
n
Mean SE
Range

Absolute Distance (tkm)
n
Mean SE
Range

Absolute Distance (rkm + tkm)
n
Mean SE
Range

11
31

11.0
31.0

11
31

Welch's two sample t:
1

Male
Female

Male
Female

5
12

Combined

6
19

Male

17
25

Female

Welch's two sample t:

1.0
1.7

0.0 - 5.0
0.0 - 20.8

5
12

9.3
9.5

2.7
1.6

0.0 - 19.2
0.0 - 22.0

7.0
9.5

1.4
1.4

0.0 - 20.8
0.0 - 22.0

5
6

2.6
9.3

1.0
2.7

0.0 - 5.0
0.0 - 19.2

6
19

8.8
9.5

1.7
1.6

0.0 - 20.8
0.0 - 22.0

t(26.8) = -0.3, p = 0.76

0.0 - 6.1
0.0 - 12.0

1.8
0.4

1.1
0.2

0.0 - 5.9
0.0 - 2.6

1.2
1.1

1.0
0.6

0.0 - 6.1
0.0 - 12.0

17
25

0.8
1.1

0.4
0.5

0.0 - 5.9
0.0 - 12.0

5
12

1.8
1.2

1.1
1.0

0.0 - 5.9
0.0 - 6.1

6
19

0.4
1.1

0.2
0.6

0.0 - 2.6
0.0 - 12.0

t(21.6) = -1.03, p = 0.31

0.8 - 19.2
1.0 - 22.0

4.4
9.2

1.0
1.7

1.9 - 7.0
1.0 - 20.8

10.5
10.6

2.4
1.5

0.8 - 19.2
1.0 - 22.0

t(9.1) = -0.043, p = 0.97
17
25

7.8
10.6

1.3
1.2

1.0 - 20.8
0.8 - 22.0

t(42.0) = -1.72, p = 0.09
5
6

t(8.6) = 0.41, p = 0.69
12
19

1.6
1.1

t(15.0) = -2.46, p = 0.03

t(79.6) = -0.68, p = 0.50
5
6

7.7
10.1

t(76.7) = -2.21, p = 0.03

t(9.7) = 0.094, p = 0.93

t(6.3) = -2.31, p = 0.06
12
19

0.7
0.4

t(4.3) = 1.28, p = 0.27

t(78.3) = -1.82, p = 0.07

Welch's two sample t:
1
2

2.6
8.8

1.5
0.8

t( 36.3) = 1.18, p = 0.25

t(8.8) = -0.07, p = 0.94

Welch's two sample t:
1
2

0.0 - 19.2
0.0 - 22.0

t(15.0) = -3.18, p = 0.006

Welch's two sample t:
1
2

1.8
1.2

t(40.2) = -2.00, p = 0.05

Welch's two sample t:
2

6.2
9.2

4.4
10.5

1.0
2.4

1.9 - 7.0
0.8 - 19.2

t(6.7) = -2.34, p = 0.05
12
19

9.2
10.6

1.7
1.5

1.0 - 20.8
1.0 - 22.0

t(25.3) = -0.63, p = 0.53

151

Table A1.12. Absolute distance mobile and stationary CCT travelled to initial overwintering areas. Note that CCT captured within overwintering areas have been
excluded. Summary includes distance travelled in mainstem (rkm), tributaries (tkm) and in total (rkm + tkm). Significant tests results are presented in bold.

Year
Combined

Winter
Behaviour

Absolute Distance (rkm)
n Mean SE
Range

Absolute Distance (tkm)
n Mean SE
Range

Stationary
Mobile

25
15

25
15

Welch's two sample t:
1

Stationary
Mobile

Welch's two sample t:
2

Stationary
Mobile

Welch's two sample t:
1
2

Combined

Welch's two sample t:
1
2

Stationary

Mobile

Welch's two sample t:

1.5
1.4

0.0 - 20.8
0.0 - 22.0

t(69.5) = -1.25, p = 0.22
11
6

7.3
6.4

2.0
1.9

0.0 - 20.8
0.5 - 11.1

t(13.5) = 0.32, p = 0.76
4
19

7.2
10.5

2.5
1.7

1.9 - 13.4
0.0 - 22.0

t(6.3) = -0.89, p = 0.40
17
23

7.0
9.9

1.4
1.5

0.0 - 20.8
0.0 - 22.0

1.0
1.1

0.4
0.5

0.0 - 5.9
0.0 -12.0

t(82.0) = -1.0, p = 0.31
11
6

0.9
0.6

0.5
0.4

0.0 - 5.9
0.0 - 2.6

t(14.9) = 0.50, p = 0.62
4
19

1.2
1.2

0.9
0.7

0.3 - 3.9
0.0 - 12.0

t(7.4) = -0.21, p = 0.84
17
23

0.8
1.2

0.4
0.6

0.0 - 5.9
0.0 -12.0

25
15

8.2
10.5

1.4
1.3

1.0 - 20.8
0.8 - 22.0

t(76.7) = -2.07, p = 0.041
6
11

8.2
7.0

1.8
2.1

1.0 - 20.8
1.1 - 13.1

t(11.9) = 0.45, p = 0.66
4
19

8.4
11.7

2.4
1.5

2.2 - 13.7
0.8 - 22.0

t(5.6) = -1.06, p = 0.33
17
23

7.8
11.1

1.3
1.3

1.0 - 20.8
0.8 - 22.0

t(79.4) = -1.56, p = 0.12

t(77.9) = -0.47, p = 0.64

t(68.8) = -1.56, p = 0.12

11
4

11
4

11
4

Welch's two sample t:
1
2

7.2
9.4

Absolute Distance (rkm + tkm)
n Mean SE
Range

7.3
7.2

2.0
2.5

0.0 - 20.8
1.9 - 13.4

t(7.0) = 0.03, p = 0.98
6
19

6.4
10.5

1.9
1.7

0.5 - 11.1
0.0 - 22.0

t(13.9) = -1.35, p = 0.20

0.9
1.2

0.5
0.9

0.0 - 5.9
0.3 - 3.9

t(5.2) = -0.26, p = 0.81
6
19

0.6
1.2

0.4
0.7

0.0 - 2.6
0.0 - 12.0

t(22.8) = -1.03, p = 0.31

8.2
8.4

1.8
2.4

1.0 - 20.8
2.2 - 13.7

t(6.6) = -0.06, p = 0.95
6
19

7.0
11.7

2.1
1.5

1.1 - 13.1
0.8 - 22.0

t(10.7) = -1.72, p = 0.11

152

Table A1.13. Summary of the number of overwintering habitats (OW) mobile CCT occupied; the mainstem river position (rkm) of final overwintering habitats
for mobile CCT relative to initial overwintering habitats; the mean distance separating overwintering habitats, and; the total absolute distance male and female
CCT moved between overwintering habitats. Significant tests results are presented in bold.
Year

Sex

Combined

Male
Female

Number of OW habitats Occupied
n
Mean SE
Range
12
17

Welch's two sample t:
1

Male
Female

Male
Female

10
19

Combined

5
5

Male

7
12

Female

Welch's two sample t:

2.6
2.7

0.2
0.2

2- 4
2- 5

3.0
2.2

0.3
0.2

2- 4
2- 3

2.3
2.9

0.2
0.3

2- 3
2- 5

5
7

3.0
2.3

0.3
0.2

2- 4
2- 3

5
5

2.2
2.9

0.2
0.3

2- 3
2- 5

t(14.2) = -2.18, p = 0.05

-0.9
-2.3

2.3
1.4

-12.1 to 12.3
-17.9 to 6.2

n

Mean Distance of
Mean SE
Range

Total Absolute Distance Moved (rkm +
n
Mean
SE
Range

21
39

6.8
4.8

12
17

-5.2
-3.6

2.8
2.3

-12.1 to 4.4
-10.4 to 1.3

7
12

2.1
-1.8

2.9
1.7

-9.3 to 12.3
-17.9 to 6.2

10
7

-4.4
-0.3

1.7
1.6

-12.1 to 4.4
-17.9 to 12.3

11
32

-5.2
2.1

2.8
2.9

-12.1 to 4.4
-9.3 to 12.3

17
43

-3.6
-1.8

2.3
1.7

-10.4 to 1.3
-17.9 to 6.2

t(8.9) = -0.64, p = 0.54

1.4
1.4

2.1 - 15.0
1.3 - 10.7

5
5

7.6
4.6

1.3
0.5

2.7 - 13.4
1.1 - 11.6

5.7
5.4

1.0
0.5

1.3 - 15.0
1.1 - 13.4

10
11

5.8
7.6

1.4
1.3

2.1 - 15.0
2.7 - 13.4

7
12

5.5
4.6

1.4
0.5

1.3 - 10.7
1.1 - 11.6

t(7.4) = 0.62, p = 0.55

2.9 to 23
1.4 to 31.3

12.6
6.3

3.3
2.0

5 to 23.5
1.3 to 11

11.8
9.4

2.4
2.6

3 to 22.2
2.2 to 33.4

t(15.9) = 0.68, p = 0.51
10
19

9.5
10.3

2.1
1.8

1.3 to 23.5
2.2 to 33.4

t(21.5) = -0.3, p = 0.76
5
7

t(18.9) = -0.93, p = 0.37
7
32

1.6
1.7

t(6.7) = 1.65, p = 0.15

t(26.0) = 0.32, p = 0.75

t(9.7) = -1.79, p = 0.10
5
12

5.8
5.5

10.4
8.2

t(26.8) = 0.98, p = 0.34

t(12.8) = 2.14, p = 0.05

t(22.1) = -1.73, p = 0.10
5
7

2.1 - 15.0
1.1 - 11.6

t(14.1) = 0.16, p = 0.88

t(10.4) = 1.15, p = 0.28
10
19

0.9
0.5

t(30.0) = 1.90, p = 0.07

t(7.8) = -0.42, p = 0.68

t(6.7) = 1.95, p = 0.09
5
12

Relative Position of OW
Mean SE
Range

t(19.0) = 0.53, p = 0.60

t(17.0) = -1.98, p = 0.06

Welch's two sample t:
1
2

12
17

t(6.8) = 2.14, p = 0.07

Welch's two sample t:
1
2

2- 4
2- 5

t(26.6) = -0.43, p = 0.67

Welch's two sample t:
1
2

0.2
0.2

t(21.2) = -0.29, p = 0.77

Welch's two sample t:
2

2.6
2.7

n

12.6
11.8

3.3
2.4

5 to 23.5
3 to 22.2

t(8) = 0.2, p = 0.85
5
12

6.3
9.4

2.0
2.6

1.3 to 11
2.2 to 33.4

t(13.9) = -0.96, p = 0.35

153

Table A1.14. Timing that staging and non-staging male and female CCT departed from final overwintering habitats in year 1 and year 2. Significant tests results
are presented in bold.
Year

Sex

Combined

Male
Female

n

Staging & Non-Staging
Median
SD
Range

n

Non-Staging
Median
SD

20
33

31-Mar
07-Apr

10
17

1-Apr
5-Apr

Two sample KS test:
1

Male
Female

Ho: Male < Female; p = 0.11, D = 0.30
12
16

Two sample KS test:
2

Male
Female

Combined

Two sample KS test:
1
2

Male

8
17

Female

Two sample KS test:

10.0
12.0

13-Mar to 14-Apr
06-Mar to 19-Apr

5
9

02-Apr
08-Apr

16.6 04-Mar to 28-Apr
9.7 28-Mar to 05-May

23-Mar
5-Apr

28
25

28-Mar
07-Apr

11.3 06-Mar to 19-Apr
12.2 04-Mar to 05-May

Ho: Year 1 < Year 2; p < 0.001, D = 0.42
12
8

28-Mar
02-Apr

10.0
16.6

13-Mar to 14-Apr
04-Mar to 28-Apr

5
8

05-Apr
08-Apr

12.0 06-Mar to 19-Apr
9.7 28-Mar to 05-May

Ho: Year 1 < Year 2; p = 0.19, D = 0.32

Staging
SD

15-Mar to 28-Apr
06-Mar to 19-Apr

10
16

30-Mar
8-Apr

3.6
3.0

5.1
4.5

15-Mar to 14-Apr
06-Mar to 19-Apr

7-Apr
7-Apr

5.6
2.3

31-Mar to 28-Apr
28-Mar to 17-Apr

14
13

28-Mar
7-Apr

3.4
2.6

06-Mar to 19-Apr
28-Mar to 28-Apr

7
7

23-Mar
7-Apr

5.1
5.6

15-Mar to 14-Apr
31-Mar to 28-Apr

5-Apr
7-Apr

4.5
2.3

06-Mar to 19-Apr
28-Mar to 17-Apr

Ho: Year 1 < Year 2; p = 0.42, D = 0.32

28-Mar
5-Apr

3
9

04-Mar to 09-Apr
20-Mar to 05-May

Ho: Non Stage < Stage; p = 0.78, D = 0.07
Ho: Non Stage < Stage; p = 0.78, D = 0.07

3.6
4.2

13-Mar to 09-Apr
20-Mar to 19-Apr

1-Apr
11-Apr

9.3
3.9

04-Mar to 01-Apr
28-Mar to 05-May

Ho: Male < Female; p = 0.03, D = 0.89
14
12

1-Apr
6-Apr

2.7
4.4

13-Mar to 19-Apr
04-Mar to 05-May

Ho: Year 1 < Year 2; p = 0.05, D = 0.35
7
3

Ho: Year 1 < Year 2; p = 0.04, D = 0.8
9
8

Two-sample KS test:
Non-Staging vs Staging CCT

Ho: Male < Female; p = 0.87, D = 0.14

Ho: Year 1 < Year 2; p = 0.001, D = 0.49
5
5

Range

Ho: Male < Female; p = 0.08, D = 0.45

Ho: Male > Female; p = 0.37, D = 0.4

Ho: Year 1 < Year 2; p = 0.06, D = 0.54
16
17

Median

Ho: Male < Female; p = 0.22, D = 0.49

Ho: Male < Female; p = 0.30, D = 0.33

Two sample KS test:
1
2

28-Mar
05-Apr

4.5
2.6

n

Ho: Male < Female; p = 0.48, D = 0.24

Ho: Male < Female, p = 0.49, D = 0.23

Two sample KS test:
1
2

13.1 04-Mar to 28-Apr
11.3 06-Mar to 05-May

Range

28-Mar
1-Apr

3.6
9.3

13-Mar to 09-Apr
04-Mar to 01-Apr

Ho: Year 1 > Year 2; p = 0.46, D = 0.43
7
9

5-Apr
11-Apr

4.2
3.9

20-Mar to 19-Apr
28-Mar to 05-May

Ho: Year 1 < Year 2; p = 0.26, D = 0.41

Ho: Non Stage < Stage; p = 0.30, D = 0.46
Ho: Non Stage < Stage; p = 0.79, D = 0.17
Ho: Non Stage > Stage; p = 0.09, D = 0.8
Ho: Non Stage < Stage; p = 0.66, D = 0.22
Ho: Non Stage < Stage; p = 0.56, D = 0.14
Ho: Non Stage < Stage; p = 0.42, D = 0.19
-

154

Table A1.15. Timing that staging and non-staging mobile and stationary CCT departed from final overwintering habitats in year 1 and year 2. Significant tests
results are presented in bold.
Year
Combined

Migration
Type

n

Staging & Non-Staging
Median
SD
Range

n

Non-Staging
Median
SD

Stationary
Mobile

24
29

05-Apr
02-Apr

12
15

04-Apr
07-Apr

Two sample KS test:
1

Stationary
Mobile

Two sample KS test:
2

Stationary
Mobile

Two sample KS test:
1
2

Combined

Two sample KS test:
1
2

Stationary

Mobile

Two sample KS test:

13.1 06-Mar to 19-Apr
10.9 21-Mar to 28-Apr

n

Median

Staging
SD

12
14

08-Apr
30-Mar

7.35 21-Mar to 19-Apr
16.2 04-Mar to 05-May

Range

Ho: Stationary > Mobile; p = 0.41, D = 0.18

Ho: Stationary < Mobile; p = 0.59, D = 0.2

Ho: Stationary > Mobile; p = 0.14, D = 0.39

18
10

9
5

9
5

05-Apr
28-Mar

11.5
10.5

06-Mar to 19-Apr
13-Mar to 19-Apr

28-Mar
28-Mar

13.7 06-Mar to 19-Apr
12.3 21-Mar to 19-Apr

09-Apr
28-Mar

8.24 21-Mar to 19-Apr
6.77 13-Mar to 28-Mar

Ho: Stationary > Mobile; p = 0.11, D = 0.41

Ho: Stationary < Mobile; p = 0.73, D = 0.22

Ho: Stationary > Mobile; p = 0.02, D = 0.78

6
19

3
10

3
9

09-Apr
07-Apr

5.89 01-Apr to 17-Apr
13.8 04-Mar to 05-May

11-Apr
7-Apr

7.0 03-Apr to 17-Apr
10.0 28-Mar to 28-Apr

07-Apr
05-Apr

5.03 01-Apr to 11-Apr
17.7 04-Mar to 05-May

Ho: Stationary > Mobile; p = 0.53, D = 0.26

Ho: Stationary > Mobile; p = 0.54, D = 0.37

Ho: Stationary > Mobile; p = 0.61, D = 0.33

28
25

14
13

14
12

28-Mar
07-Apr

11.3 06-Mar to 19-Apr
12.2 04-Mar to 05-May

Ho: Year 1 < Year 2; p < 0.001, D = 0.42
18
6

Two sample KS test:
1
2

10.6 06-Mar to 19-Apr
13.6 04-Mar to 05-May

Range

05-Apr
09-Apr

11.5
5.89

06-Mar to 19-Apr
01-Apr to 17-Apr

Ho: Year 1 < Year 2; p = 0.26, D = 0.39
10
19

28-Mar
07-Apr

10.5 13-Mar to 19-Apr
13.8 04-Mar to 05-May

Ho: Year 1 < Year 2; p = 0.004; D = 0.64

28-Mar
07-Apr

12.8 06-Mar to 19-Apr
9.2 28-Mar to 28-Apr

Ho: Year 1 < Year 2; p = 0.001, D = 0.49
9
3

28-Mar
11-Apr

13.7 06-Mar to 19-Apr
7.0 03-Apr to 17-Apr

28-Mar
7-Apr

12.3 21-Mar to 19-Apr
10.0 28-Mar to 28-Apr

Ho: Year 1 < Year 2; p = 0.19, D = 0.5

10 13-Mar to 19-Apr
15.3 04-Mar to 05-May

Ho: Year 1 < Year 2; p = 0.05, D = 0.35
9
3

Ho: Year 1 < Year 2; p = 0.25, D = 0.56
5
10

01-Apr
06-Apr

09-Apr
07-Apr

8.24
5.03

21-Mar to 19-Apr
01-Apr to 11-Apr

Ho: Year 1 < Year 2; p = 0.80, D = 0.22
5
9

28-Mar
05-Apr

6.77 13-Mar to 28-Mar
17.7 04-Mar to 05-May

Ho: Year 1 < Year 2; p = 0.02, D = 0.78

Two-sample KS test:
Non-Staging vs Staging CCT
Ho: Non Stage > Stage; p = 0.42, D = 0.19
Ho: Non Stage > Stage; p = 0.56, D = 0.14
Ho: Non Stage < Stage; p = 0.37, D = 0.33
Ho: Non Stage > Stage; p = 0.45, D = 0.4
Ho: Non Stage = Stage; p = 0.72, D = 0.33
Ho: Non Stage = Stage; p = 0.8, D = 0.16
Ho: Non Stage > Stage; p = 0.41, D = 0.25
Ho: Non Stage = Stage; p = 0.47, D = 0.25
-

155

Table A1.16. Summary of absolute distances travelled by male and female CCT from overwintering to
spawning habitats, from overwinter to staging habitats, and from staging to spawning habitats in year 1 and
year 2. Significant tests results are presented in bold.
Year

Sex

Combined

Male
Female

Welch's two sample t:
1

Male
Female

Welch's two sample t:
2

Male
Female

OW to Stage
n Mean SE Range
10
16

Combined

Welch's two sample t:
1
2

Male

Welch's two sample t:
1
2

Female

Welch's two sample t:

3.5 0.1 - 36.2 10
1.2 0.1 - 14.8 14

3.2
5.7

0.5 0.8 - 5.7
1.0 1.7 - 14.0

t(11.0) = 0.47, p = 0.65

t(-2.3) = 19.06, p = 0.04

7
7

7
6

3.5
4.4

1.2 0.1 - 9.5
1.9 0.2 - 14.8

3.2
4.2

0.6 0.8 - 5.2
0.9 1.7 - 8.1

t(10.3) = -0.42, p = 0.68

t(-1.0) = 8.27, p = 0.37

3
9

3
8

Welch's two sample t:
1
2

6.2
4.5

Stage to Spawn
n Mean SE Range

12.7 11.8 0.7 - 36.2
4.6 1.5 0.1 - 14.0
t(2.1) = 0.68, p = 0.56

14
12

4.0
6.6

3.1
6.9

1.4 0.8 - 5.7
1.5 2.4 - 14.0

t(-1.8) = 6.82, p = 0.12

1.1 0.1 - 14.8 13
2.9 0.1 - 36.2 11

3.6
5.8

0.5 0.8 - 8.1
1.3 0.8 - 14.0

t(14.0) = -0.85, p = 0.41

t(-1.6) = 13.42, p = 0.13

7
3

7
3

3.5 1.2 0.1 - 9.5
12.7 11.8 0.7 - 36.2

3.2
3.1

0.6 0.8 - 5.2
1.4 0.8 - 5.7

t(2.0) = -0.78, p = 0.52

t(0.01) = 2.64, p = 0.99

7
9

6
8

4.4
4.6

1.9 0.2 - 14.8
1.5 0.1 - 14.0

t(12.4) = -0.07, p = 0.94

4.2
6.9

0.9 1.7 - 8.1
1.5 2.4 - 14.0

t(-1.5) = 11.03, p = 0.17

156

Table A1.17. Summary of absolute distances travelled by stationary and mobile CCT from overwintering to
spawning habitats, from overwinter to staging habitats, and from staging to spawning habitats in year 1 and
year 2. Significant tests results are presented in bold.
Year
Combined

Migration
Type

OW to Stage
n Mean SE Range

Stationary
Mobile

12
14

Welch's two sample t:
1

Stationary
Mobile

Welch's two sample t:
2

Stationary
Mobile

Welch's two sample t:
1
2

Combined

Welch's two sample t:
1
2

Stationary

Mobile

Welch's two sample t:

0.6 0.1 - 5.8 11
2.6 0.1 - 36.2 13

3.6
5.5

0.6 0.8 - 8.1
1.1 0.8 - 14.0

t(14.5) = -1.80, p = 0.09

t(-1.5) = 18.94, p = 0.16

9
5

8
5

2.6
6.3

0.8 0.1 - 5.8
2.6 1.4 - 14.8

3.3
4.2

0.8 0.8 - 8.1
0.6 2.9 - 5.6

t(4.7) = -1.39, p = 0.23

t(-1.0) = 10.97, p = 0.33

3
9

3
8

2.6
8.0

1.0 1.2 - 4.6
3.9 0.1 - 36.2

t(9.0) = -1.35, p = 0.21
14
12

4.0
6.6

4.7
6.3

1.0 2.7 - 5.7
1.7 0.8 - 14

t(-0.8) = 8.97, p = 0.44

1.1 0.1 - 14.8 13
2.9 0.1 - 36.2 11

3.6
5.8

0.5 0.8 - 8.1
1.3 0.8 - 14.0

t(14.0) = -0.85, p = 0.41

t(-1.6) = 13.42, p = 0.13

9
3

8
3

Welch's two sample t:
1
2

2.6
7.4

Stage to Spawn
n Mean SE Range

2.6
2.6

0.8 0.1 - 5.8
1.0 1.2 - 4.6

t(4.6) = 0.02, p = 0.99
5
9

6.3
8.0

2.6 1.4 - 14.8
3.9 0.1 - 36.2

t(12) = -0.35, p = 0.73

3.3
4.7

0.8 0.8 - 8.1
1.0 2.7 - 5.7

t(-1.1) = 4.77, p = 0.32
5
8

4.2
6.3

0.6 2.9 - 5.6
1.7 0.8 - 14.0

t(-1.1) = 8.38, p = 0.29

157

Table A1.18. Median timing that male and female CCT arrived in, and departed from, pre-spawn staging habitats in year 1 and year 2. Significant tests results
are presented in bold.

Year

Sex

1
2

Combined

n

Arrival to pre-spawn staging
Median
SD
Range

n

Departure from pre-spawn staging
Median
SD
Range

12
10

11-Apr
12-Apr

11
10

19-Apr
27-Apr

Two sample KS test:
Combined

Male
Female

Male
Female

9
13

Male
Female

6
6

Male

3
7

Female
Two sample KS test:

28-Mar to 23-Apr
28-Mar to 01-May

8
13

7-Apr
14-Apr

9.0
11.7

28-Mar to 19-Apr
28-Mar to 01-May

9-Apr
14-Apr

8.7
6.7

07-Apr to 23-Apr
11-Apr to 28-Apr

6
3

7-Apr
9-Apr

9.0
8.7

28-Mar to 19-Apr
07-Apr to 23-Apr

5
6

14-Apr
14-Apr

11.7
6.7

28-Mar to 01-May
11-Apr to 28-Apr

Ho: Year 1 < Year 2; p = 0.49, D = 0.33

17-Apr
23-Apr

6.7
9.9

05-Apr to 28-Apr
28-Mar to 06-May

14-Apr
19-Apr

6.5
12.6

05-Apr to 22-Apr
28-Mar to 06-May

Ho: Male < Female; p = 0.68, D = 0.27
3
7

17-Apr
28-Apr

6.4
5.6

17-Apr to 28-Apr
14-Apr to 01-May

Ho: Male < Female; p = 0.32, D = 0.52
5
3

Ho: Year 1 < Year 2; p = 0.37, D = 0.5
6
7

28-Mar to 06-May
14-Apr to 01-May

Ho: Male < Female; p = 0.184, D = 0.41

Ho: Male < Female; p = 0.15, D = 0.67

Two sample KS test:
1
2

8.9
9.1

Ho: Male < Female; p = 0.51, D = 0.33

Two sample KS test:
1
2

9-Apr
14-Apr

10.0
6.0

Ho: Year 1 < Year 2; p < 0.001, D = 0.61

Ho: Male < Female; p = 0.061, D = 0.51

Two sample KS test:
2

28-Mar to 01-May
07-Apr to 28-Apr

Ho: Year 1 < Year 2; p = 0.023, D = 0.42

Two sample KS test:
1

10.5
7.1

14-Apr
17-Apr

6.5
6.4

05-Apr to 22-Apr
17-Apr to 28-Apr

Ho: Year 1 < Year 2; p = 0.26, D = 0.6
6
7

19-Apr
28-Apr

12.6
5.6

28-Mar to 06-May
14-Apr to 01-May

Ho: Year 1 < Year 2; p = 0.046, D = 0.69

158

Table A1.19. Median timing that mobile and stationary CCT arrived in, and departed from, staging habitats in year 1 and year 2. Significant tests results are
presented in bold.

Year

Migration Type

1
2

Combined

n

Arrival to pre-spawn staging
Median
SD
Range

n

Departure from pre-spawn staging
Median
SD
Range

12
10

11-Apr
12-Apr

11
10

19-Apr
27-Apr

Two sample KS test:
Combined

Stationary
Mobile

Stationary
Mobile

10
12

Stationary
Mobile

7
5

Stationary

3
7

Mobile
Two sample KS test:

28-Mar to 01-May
28-Mar to 28-Apr

9
12

14-Apr
5-Apr

12.3
6.2

28-Mar to 01-May
28-Mar to 14-Apr

11-Apr
17-Apr

2.5
7.8

09-Apr to 14-Apr
07-Apr to 28-Apr

7
3

14-Apr
11-Apr

12.3
2.5

28-Mar to 01-May
09-Apr to 14-Apr

6
5

5-Apr
17-Apr

6.2
7.8

28-Mar to 14-Apr
07-Apr to 28-Apr

Ho: Year 1 < Year 2; p = 0.081, D = 0.66

19-Apr
21-Apr

10.7
7.8

28-Mar to 06-May
05-Apr to 01-May

20-Apr
14-Apr

12.8
5.7

28-Mar to 06-May
05-Apr to 19-Apr

Ho: Stationary < Mobile; p = 0.26, D = 0.5
3
7

17-Apr
28-Apr

6.8
4.7

14-Apr to 27-Apr
17-Apr to 01-May

Ho: Stationary < Mobile; p = 0.117, D = 0.71
6
3

Ho: Year 1 > Year 2; p = 0.46, D = 0.43
5
7

28-Mar to 06-May
14-Apr to 01-May

Ho: Stationary < Mobile; p = 0.383, D = 0.31

Ho: Stationary < Mobile; p = 0.25, D = 0.57

Two sample KS test:
1
2

10.2
9.0

Ho: Stationary < Mobile; p = 0.21, D = 0.51

Two sample KS test:
1
2

14-Apr
11-Apr

10.0
6.0

Ho: Year 1 < Year 2; p < 0.001, D = 0.61

Ho: Stationary > Mobile; p = 0.69, D = 0.18

Two sample KS test:
2

28-Mar to 01-May
07-Apr to 28-Apr

Ho: Year 1 < Year 2; p = 0.023, D = 0.42

Two sample KS test:
1

10.5
7.1

20-Apr
17-Apr

12.8
6.8

28-Mar to 06-May
14-Apr to 27-Apr

Ho: Year 1 > Year 2; p = 0.64, D = 0.33
5
7

14-Apr
28-Apr

5.7
4.7

05-Apr to 19-Apr
17-Apr to 01-May

Ho: Year 1 < Year 2; p = 0.014, D = 0.86

159

Table A1.20. Comparison of the total absolute distance staging and non-staging male and female CCT travelled
from overwintering habitats to spawn. Significant tests results are presented in bold.
Year

Sex

Combined

Male
Female

Welch's two sample t:
1

Male
Female

Welch's two sample t:
2

Male
Female

OW to Spawn (Staging)
n Mean SE Range

OW to Spawn (Non-staging) Welch's two sample t:
n Mean SE
Range
Staging vs. Non-Staging

10
14

10 12.5 3.5
13 16.5 2.7

Combined

Welch's two sample t:
1
2

Male

Welch's two sample t:
1
2

Female

Welch's two sample t:

3.3 2.5 - 37.0
1.3 1.9 - 17.8

t(0.0) = 11.68, p = 0.98
7
6

6.3
8.4

1.6 2.5 - 14.0
2.2 1.9 - 17.8

3
8

15.0 11.0 3.6 - 37.0
9.5 1.6 2.9 - 16.4

5
7

1.3 1.9 - 17.8
2.9 2.9 - 37.0

5
6

6.3 1.6 2.5 - 14.0
15.0 11.0 3.6 - 37.0

8.4
9.5

2.2 1.9 - 17.8
1.6 2.9 - 16.4

t(-0.4) = 9.76, p = 0.68

8.2 1.7
22.4 4.5

12 13.6 2.9
11 16.0 3.3

2.4 - 12.7
7.1 - 35.1

2.5 - 33.0
2.4 - 35.1

t(20.3) = -0.53, p = 0.60
5
5

t(-0.8) = 2.08, p = 0.51
6
8

2.5 - 33.0
2.8 - 17.5

t(6.3) = -2.94, p = 0.02

t(-1.2) = 13.87, p = 0.26
7
3

16.7 6.5
11.4 2.1

t(4.8) = 0.77, p = 0.48

t(0.5) = 2.09, p = 0.67
13 7.3
11 11.0

2.4 - 33.0
2.8 - 35.1

t(18.4) = -0.91, p = 0.38

t(-0.8) = 9.29, p = 0.46

Welch's two sample t:
1
2

8.9
9.0

7
6

16.7 6.5
8.2 1.7

t(18.0) = -0.74, p = 0.47
t(17.0) = -2.46, p = 0.02
t(4.5) = -1.55, p = 0.19
t(10.7) = -1.01, p = 0.33
t(2.1) = 0.61, p = 0.60
t(6.3) = -2.69, p = 0.03
t(15.2) = -2.00, p = 0.06
t(19.7) = -1.12, p = 0.28
-

2.5 - 33.0
2.4 - 12.7

-

t(4.5) = 1.26, p = 0.27

-

11.4 2.1
22.4 4.5

2.8 - 17.5
7.1 - 35.1

-

t(7.1) = -2.21, p = 0.06

-

160

Table A1.21. Comparison of the total absolute distance staging and non-staging mobile and stationary CCT
travelled from overwintering habitats to spawn. Significant tests results are presented in bold.
Year
Combined

Migration
Type

OW to Spawn (Staging)
n Mean SE Range

OW to Spawn (Non-staging) Welch's two sample t:
n Mean SE
Range
Staging vs. Non-Staging

Stationary
Mobile

11 5.6
13 11.9

11 12.9 2.6
12 16.5 3.4

Welch's two sample t:
1

Stationary
Mobile

t(-2.4) = 14.36, p = 0.03
8
5

Welch's two sample t:
2

Stationary
Mobile

Welch's two sample t:
1
2

Combined

Welch's two sample t:
1
2

Stationary

Welch's two sample t:
1
2

Mobile

Welch's two sample t:

0.8 1.9 - 9.4
2.5 2.9 - 37.0

5.3
10.5

1.0 1.9 - 9.4
2.4 4.8 - 17.8

t(19.8) = -0.84, p = 0.41
8
4

t(-2) = 5.54, p = 0.10
3
8

6.4
12.8

1.0 4.5 - 7.4
3.9 2.9 - 37.0

1.3 1.9 - 17.8
2.9 2.9 - 37.0

3
8

5.3
6.4

1.0 1.9 - 9.4
1.0 4.5 - 7.4

10.5
12.8

2.4 4.8 - 17.8
3.9 2.9 - 37.0

t(-0.5) = 10.65, p = 0.63

12.9 2.9
17.1 4.5

12 13.6 2.9
11 16.0 3.3

7.1 - 16.3
2.4 - 35.1

2.5 - 33.0
2.4 - 35.1

t(20.3) = -0.53, p = 0.59
8
3

t(-0.8) = 6.86, p = 0.44
5
8

2.5 - 32.1
7.6 - 33.0

t(8.7) = -0.78, p = 0.46

t(-1.2) = 13.87, p = 0.26
8
3

12.8 3.4
15.3 6.0

t(5) = -0.35, p = 0.74

t(-1.6) = 7.77, p = 0.15
13 7.3
11 11.0

2.5 - 32.1
2.4 - 35.1

4
8

12.8 3.4
12.9 2.9

t(11.9) = -2.73, p = 0.02
t(20.4) = -1.08, p = 0.29
t(8.3) = -2.11, p = 0.07
t(3.9) = -0.73, p = 0.51
t(2.1) = 0.87, p = 0.47
t(12.0) = -1.45, p = 0.17
t(15.2) = -2.00, p = 0.06
t(19.7) = -1.12, p = 0.28
-

2.5 - 32.1
7.1 - 16.3

-

t(7.3) = -0.02, p = 0.98

-

15.3 6.0
17.1 4.5

7.6 - 33.0
2.4 - 35.1

-

t(6.4) = -0.25, p = 0.81

-

161

Table A1.22. Date that male and female staging and non-staging CCT arrived in spawning tributaries in year 1 and year 2. Comparisons between staging and
non-staging CCT are presented in the final column. Significant tests results are presented in bold.
Year

Sex

Combined

Male
Female

Two sample KS test:
1

Male
Female

Two sample KS test:
2

Male
Female

Two sample KS test:
1
2

Combined

Two sample KS test:
1
2

Male

Two sample KS test:
1
2

Female

Two sample KS test:

n

Staging & Non-Staging
Median
SD
Range

n

Median

20
27

23-Apr
28-Apr

10
13

16-Apr
27-Apr

11.0
10.2

28-Mar to 05-May
05-Apr to 09-May

Ho: Male < Female; p = 0.29, D = 0.23
12
13

19-Apr
27-Apr

10.3
11.5

28-Mar to 29-Apr
05-Apr to 06-May

01-May
01-May

9.9
8.9

11-Apr to 05-May
11-Apr to 09-May

5
7

19-Apr
01-May

11.0
9.0

28-Mar to 06-May
11-Apr to 09-May

19-Apr
01-May

10.3
9.9

28-Mar to 29-Apr
11-Apr to 05-May

27-Apr
01-May

11.5
8.9

05-Apr to 06-May
11-Apr to 09-May

Ho: Year 1 < Year 2; p = 0.28, D = 0.31

Staging
SD

10
14

27-Apr
1-May

9.0 05-Apr to 05-May
11.2 05-Apr to 09-May

9.6
10.4

28-Mar to 19-Apr
06-Apr to 01-May

1-May
25-Apr

11.8
8.1

11-Apr to 05-May
11-Apr to 01-May

12
11

19-Apr
28-Apr

11.0
9.4

28-Mar to 01-May
11-Apr to 05-May

Ho: Year 1 < Year 2; p = 0.04, D = 0.38
5
5

14-Apr
1-May

9.6
11.8

28-Mar to 19-Apr
11-Apr to 05-May

7
6

27-Apr
25-Apr

10.4
8.1

06-Apr to 01-May
11-Apr to 01-May

Ho: Year 1 > Year 2; p = 0.59, D = 0.29

27-Apr
26-Apr

9.0 05-Apr to 29-Apr
13.6 05-Apr to 06-May

Ho: Male < Female; p = 0.20, D = 0.50
3
8

1-May
1-May

3.5
9.4

28-Apr to 05-May
11-Apr to 09-May

Ho: Male > Female; p = 0.76, D = 0.25
13
11

27-Apr
1-May

10.9 05-Apr to 06-May
8.1 11-Apr to 09-May

Two sample KS Test:
Non-staging vs Staging CCT
Ho: Non-Staging < Staging; p = 0.20, D = 0.40
Ho: Non-Staging < Staging; p = 0.22, D = 0.34
Ho: Non-Staging < Staging; p = 0.15, D = 0.57
Ho: Non-Staging < Staging; p = 0.49, D = 0.33
Ho: Non-Staging < Staging; p = 0.55, D = 0.40
Ho: Non-Staging < Staging; p = 0.30, D = 0.42
Ho: Non-Staging < Staging; p = 0.14, D = 0.28
Ho: Non-Staging < Staging; p = 0.20, D = 0.27

Ho: Year 1 < Year 2; p = 0.002, D = 0.51

-

7
3

-

Ho: Year 1 < Year 2; p = 0.17, D = 0.60
7
6

Range

Ho: Male < Female; p = 0.10, D = 0.44

Ho: Male > Female; p = 0.68, D = 0.27

Ho: Year 1 < Year 2; p = 0.01, D = 0.67
13
14

14-Apr
27-Apr

5
6

Ho: Year 1 < Year 2; p < 0.001, D = 0.44
12
8

28-Mar to 05-May
06-Apr to 01-May

Median

Ho: Male < Female; p = 0.15, D = 0.57

Ho: Male < Female; p = 0.89, D = 0.11
25
22

12.2
9.1

n

Ho: Male < Female; p = 0.32, D = 0.32

Ho: Male < Female; p = 0.16, D = 0.38
8
14

Non-Staging
SD
Range

27-Apr
1-May

9.0
3.5

05-Apr to 29-Apr
28-Apr to 05-May

Ho: Year 1 < Year 2; p = 0.05, D = 0.86
6
8

26-Apr
1-May

13.6 05-Apr to 06-May
9.4 11-Apr to 09-May

Ho: Year 1 < Year 2; p = 0.47, D = 0.33

-

162

Table A1.23. Date that mobile and stationary staging and non-staging CCT arrived in spawning tributaries in year 1 and year 2. Comparisons between staging
and non-staging CCT are presented in the final column. Significant tests results are presented in bold.
Year

Migration Type

Combined

Stationary
Mobile

Two sample KS test:
1

Stationary
Mobile

Two sample KS test:
2

Stationary
Mobile

Two sample KS test:
1
2

Combined

n

Staging & Non-Staging
Median
SD
Range

n

Median

Non-Staging
SD
Range

n

Median

Staging
SD

22
25

20-Apr
01-May

11
12

19-Apr
27-Apr

10.9
10.0

11
13

27-Apr
1-May

10.4
8.8

Stationary

16
9

Mobile

Two sample KS test:

19-Apr
27-Apr

11.1
10.2

28-Mar to 01-May
05-Apr to 06-May

Ho: Stationary < Mobile; p = 0.45, D = 0.26
6
16

25-Apr
01-May

8.1
9.4

11-Apr to 01-May
11-Apr to 09-May

Ho: Stationary < Mobile; p = 0.33, D = 0.35
25
22

19-Apr
01-May

11.0
9.0

28-Mar to 06-May
11-Apr to 09-May

16
6

19-Apr
25-Apr

11.1
8.1

28-Mar to 01-May
11-Apr to 01-May

8
4

27-Apr
01-May

10.2
9.4

05-Apr to 06-May
11-Apr to 09-May

Ho: Year 1 < Year 2; p = 0.08, D = 0.47

16-Apr
23-Apr

11.8
10.4

28-Mar to 01-May
05-Apr to 27-Apr

Two sample KS Test:
Non-staging vs Staging CCT

05-Apr to 01-May
11-Apr to 09-May

Ho: Non-Staging < Staging; p = 0.44, D = 0.27
Ho: Non-Staging < Staging; p = 0.21, D = 0.35

Ho: Stationary < Mobile; p = 0.05, D = 0.5
8
5

24-Apr
29-Apr

10.9
10.0

05-Apr to 01-May
14-Apr to 06-May

Ho: Stationary < Mobile; p = 0.72, D = 0.25

Ho: Stationary < Mobile; p = 0.25, D = 0.48

3
8

3
8

23-Apr
1-May

8.7
10.0

11-Apr to 28-Apr
11-Apr to 05-May

Ho: Stationary < Mobile; p = 0.18, D = 0.63
12
11

19-Apr
28-Apr

11.0
9.4

28-Mar to 01-May
11-Apr to 05-May

8
3

16-Apr
23-Apr

11.8
8.7

28-Mar to 01-May
11-Apr to 28-Apr

13
11

23-Apr
1-May

10.4
10.0

05-Apr to 27-Apr
11-Apr to 05-May

Ho: Year 1 < Year 2; p = 0.12, D = 0.63

8.1
8.4

17-Apr to 01-May
11-Apr to 09-May

27-Apr
1-May

10.9
8.1

05-Apr to 06-May
11-Apr to 09-May

Ho: Year 1 < Year 2; p = 0.002, D = 0.51
8
3

Ho: Year 1 < Year 2; p = 0.47, D = 0.42
4
8

1-May
1-May

Ho: Stationary < Mobile; p = 0.54, D = 0.38

Ho: Year 1 < Year 2; p = 0.04, D = 0.38

Ho: Year 1 < Year 2; p = 0.29, D = 0.38
9
16

28-Mar to 01-May
05-Apr to 05-May

Ho: Stationary < Mobile; p = 0.33, D = 0.31

Ho: Year 1 < Year 2; p < 0.001, D = 0.44

Two sample KS test:
1
2

28-Mar to 01-May
05-Apr to 09-May

Ho: Stationary < Mobile; p = 0.07, D = 0.33

Two sample KS test:
1
2

10.6
9.7

Range

24-Apr
1-May

10.9
8.1

05-Apr to 01-May
17-Apr to 01-May

Ho: Year 1 < Year 2; p = 0.28, D = 0.54
5
8

29-Apr
1-May

10.0
8.4

14-Apr to 06-May
11-Apr to 09-May

Ho: Year 1 < Year 2; p = 0.47, D = 0.35

Ho: Non-Staging < Staging; p = 0.32, D = 0.38
Ho: Non-Staging < Staging; p = 0.20, D = 0.60
Ho: Non-Staging < Staging; p = 0.26, D = 0.67
Ho: Non-Staging < Staging; p = 0.61, D = 0.25
Ho: Non-Staging < Staging; p = 0.14, D = 0.28
Ho: Non-Staging < Staging; p = 0.20, D = 0.27
-

163

Table A1.24. Summary of the date that male and female staging and non-staging CCT arrived at maximum upstream relocation positions in year 1 and year 2.
Note that spawn date is estimated as the median date of maximum upstream relocation position. Values presented in the last column of the table compare the
arrival timing of staging and non-staging CCT. Significant tests results are presented in bold.
Year

Sex

Combined

Male
Female

Two sample KS test:
1

Male
Female

Two sample KS test:
2

Male
Female

Two sample KS test:
1
2

Combined

Two sample KS test:
1
2

Male

Two sample KS test:
1
2

Female

Two sample KS test:

Staging & Non-Staging
n Median
SD
Range

n Median

Non-Staging
SD

19 27-Apr
25 01-May

9 19-Apr
12 30-Apr

12.0
11.5

9.7
10.9

09-Apr to 15-May
06-Apr to 17-May

Ho: Male < Female; p = 0.61, D = 0.23
11 27-Apr
12 27-Apr

7.4
12.1

09-Apr to 04-May
06-Apr to 17-May

10.3
8.4

17-Apr to 15-May
17-Apr to 15-May

4
7

10.0
8.9

06-Apr to 17-May
17-Apr to 15-May

5
5

7.4
10.3

09-Apr to 04-May
17-Apr to 15-May

12.1
8.4

06-Apr to 17-May
17-Apr to 15-May

Ho: Year 1 < Year 2; p = 0.10, D = 0.43

19-Apr
27-Apr

5-May
1-May

11 19-Apr
10 1-May

10 28-Apr
13 5-May

7.0
9.9

7.4
14.2

09-Apr to 27-Apr
06-Apr to 17-May

12.9
6.8

17-Apr to 15-May
17-Apr to 05-May

12.1
9.8

06-Apr to 17-May
17-Apr to 15-May

4
5

19-Apr
5-May

7.4
12.9

09-Apr to 27-Apr
17-Apr to 15-May

7
5

27-Apr
1-May

14.2
6.8

06-Apr to 17-May
17-Apr to 05-May

Ho: Year 1 < Year 2; p = 0.45, D = 0.37

Two sample KS Test:
Non-staging vs Staging CCT

14-Apr to 09-May
14-Apr to 15-May

Ho: Non-Staging < Staging; p = 0.14, D = 0.46
Ho: Non-Staging < Staging; p = 0.03, D = 0.53

27-Apr
27-Apr

6.1
9.9

14-Apr to 04-May
14-Apr to 06-May

Ho: Male < Female; p = 0.39, D = 0.40
3
8

6-May
7-May

2.1
8.4

05-May to 09-May
17-Apr to 15-May

Ho: Male < Female; p = 0.76, D = 0.25
12 27-Apr
11 6-May

7
3

Ho: Year 1 < Year 2; p = 0.2, D = 0.60
7
5

Range

Ho: Male < Female; p = 0.18, D = 0.39

Ho: Year 1 < Year 2; p = 0.02, D = 0.43

Ho: Year 1 < Year 2; p = 0.005, D = 0.75
12 27-Apr
13 05-May

09-Apr to 15-May
06-Apr to 17-May

Ho: Male > Female; p = 0.45, D = 0.40

Ho: Year 1 < Year 2; p < 0.001, D = 0.54
11 27-Apr
8 05-May

Staging
SD

Ho: Male < Female; p = 0.39, D = 0.43

Ho: Male < Female; p = 0.69, D = 0.19
23 27-Apr
21 05-May

n Median

Ho: Male < Female; p = 0.53, D = 0.25

Ho: Male > Female; p = 0.30, D = 0.33
8 05-May
13 05-May

Range

5
8

7.5
7.1

14-Apr to 06-May
17-Apr to 15-May

Ho: Non-Staging < Staging; p = 0.15, D = 0.61
Ho: Non-Staging < Staging; p = 0.62, D = 0.29
Ho: Non-Staging < Staging; p = 0.55, D = 0.40
Ho: Non-Staging < Staging; p = 0.06, D = 0.68
Ho: Non-Staging < Staging; p = 0.13, D = 0.30
Ho: Non-Staging < Staging; p = 0.004, D = 0.51

Ho: Year 1 < Year 2; p < 0.001, D = 0.74

-

27-Apr
6-May

-

6.1
2.1

14-Apr to 04-May
05-May to 09-May

Ho: Year 1 < Year 2; p = 0.02, D = 1.0

-

27-Apr
7-May

-

9.9
8.4

14-Apr to 06-May
17-Apr to 15-May

Ho: Year 1 < Year 2; p = 0.21, D = 0.50

-

164

Table A1.25. Summary of the date that mobile and stationary staging and non-staging CCT arrived at maximum upstream relocation positions in year 1 and
year 2. Note that spawn date is estimated as the median date of maximum upstream relocation position. Values presented in the last column of the table
compare the arrival timing of staging and non-staging CCT. Significant tests results are presented in bold.
Year

Migration Type

Combined

Stationary
Mobile

Staging & Non-Staging
n Median
SD
Range

n Median

Non-Staging
SD

20 27-Apr
24 05-May

9 27-Apr
12 29-Apr

9.7
12.4

9.4
10.1

06-Apr to 09-May
09-Apr to 17-May

Range

n Median

Staging
SD

Range

Two sample KS Test:
Non-staging vs Staging CCT

06-Apr to 01-May
09-Apr to 17-May

11 27-Apr
12 5-May

9.2
5.5

14-Apr to 09-May
27-Apr to 15-May

Ho: Non-Staging < Staging; p = 0.27, D = 0.36
Ho: Non-Staging < Staging; p = 0.12, D = 0.42

Two sample KS test:

Ho: Stationary < Mobile; p = 0.02, D = 0.43

Ho: Stationary < Mobile; p = 0.17, D = 0.42

Ho: Stationary < Mobile; p = 0.03, D = 0.55

1

15 27-Apr
8 27-Apr

7
4

8
4

Stationary
Mobile

9.2
11.1

06-Apr to 06-May
09-Apr to 17-May

19-Apr
23-Apr

10.1
16.1

06-Apr to 01-May
09-Apr to 17-May

27-Apr
28-Apr

8.4
4.1

14-Apr to 06-May
27-Apr to 06-May

Two sample KS test:

Ho: Stationary < Mobile; p = 0.57, D = 0.23

Ho: Stationary < Mobile; p = 0.73, D = 0.25

Ho: Stationary < Mobile; p = 0.26, D = 0.50

2

5 01-May
16 05-May

2
8

3
8

Stationary
Mobile

8.5
9.2

17-Apr to 09-May
17-Apr to 15-May

30-Apr
3-May

1.4
11.1

29-Apr to 01-May
17-Apr to 15-May

Two sample KS test:

Ho: Stationary < Mobile; p = 0.39, D = 0.35

Ho: Stationary < Mobile; p = 0.45, D = 0.50

1
2

23 27-Apr
21 05-May

11 19-Apr
10 1-May

Combined

Two sample KS test:
1
2

Stationary

Two sample KS test:
1
2

Mobile

Two sample KS test:

10.0
8.9

06-Apr to 17-May
17-Apr to 15-May

Ho: Year 1 < Year 2; p < 0.001, D = 0.54
15 27-Apr
5 01-May

9.2
8.5

06-Apr to 06-May
17-Apr to 09-May

11.1
9.2

09-Apr to 17-May
17-Apr to 15-May

Ho: Year 1 < Year 2; p = 0.03, D = 0.56

06-Apr to 17-May
17-Apr to 15-May

7
2

19-Apr
30-Apr

10.1
1.4

06-Apr to 01-May
29-Apr to 01-May

12 27-Apr
11 6-May

8
3

Ho: Year 1 < Year 2; p = 0.2, D = 0.71
4
8

23-Apr
3-May

16.1
11.1

09-Apr to 17-May
17-Apr to 15-May

Ho: Year 1 < Year 2; p = 0.47, D = 0.38

11.9
3.8

17-Apr to 09-May
05-May to 15-May

Ho: Stationary < Mobile; p = 0.62, D = 0.33

Ho: Year 1 < Year 2; p = 0.02, D = 0.43

Ho: Year 1 < Year 2; p = 0.12, D = 0.53
8 27-Apr
16 05-May

12.1
9.8

6-May
7-May

4
8

7.5
7.1

14-Apr to 06-May
17-Apr to 15-May

Ho: Non-Staging < Staging; p = 0.54, D = 0.29
Ho: Non-Staging < Staging; p = 0.37, D = 0.50
Ho: Non-Staging < Staging; p = 0.34, D = 0.67
Ho: Non-Staging < Staging; p = 0.14, D = 0.50
Ho: Non-Staging < Staging; p = 0.13, D = 0.30
Ho:Non-Staging < Staging; p = 0.004, D = 0.51

Ho: Year 1 < Year 2; p < 0.001, D = 0.74

-

27-Apr
6-May

-

8.4
11.9

14-Apr to 06-May
17-Apr to 09-May

Ho: Year 1 < Year 2; p = 0.28, D = 0.54

-

28-Apr
7-May

-

4.1
3.8

27-Apr to 06-May
05-May to 15-May

Ho: Year 1 < Year 2; p = 0.05, D = 0.75

-

165

Table A1.26. Summary of the number and spawning position of and the mainstem (rkm) and tributary position (tkm) of spawning habitats within major and
minor tributaries of the Kitimat River and their secondary and tertiary channels. Note that major and minor tributaries flow directly into the Kitimat River while
secondary and tertiary tributaries confluence with major and minor tributaries, confluence position describes the location that secondary and tertiary
tributaries confluence with major and minor tributaries, while spawning position describes the distance CCT travelled within secondary and tertiary tributaries
to spawn.
Main Channel Spawning CCT
Spawning Water Body

rkm

2° and 3° Spawning CCT

n

Spawning Position (tkm)
Mean SE
Range

n

Confluence Position (tkm)
Mean SE
Range

All Spawning CCT

Spawning Position (tkm)
Mean
SE
Range

n

Spawning Position (tkm)
Mean SE
Range

Hirsch Creek
Big Wedeene
Little Wedeene
Nalbeelah Creek
Humphrey Creek
Deception Creek
Cecil Creek
Chist Creek
McKay Creek

15.7
21.4
20.1
24.8
29.7
30.4
32.6
44.2
48.3

0
2
0
4
1
2
5
1
1

26.5
4.9
2.4
2.5
6.3
5.8
2.2

4.4
1.0
0.0
2.3
-

22.1 to 30.9
1.9 to 6.3
2.5 to 2.5
2.5 to 13.2
-

5
6
2
0
0
0
3
1
1

2.5
9.5
2.6
5.6
0.3
1.0

1.4
2.9
0.0
1.5
-

0.4 to 7.4
5.2 to 23.3
2.6 to 2.6
2.6 to 7.3
-

2.0
0.8
2.9
1.4
0.2
0.5

0.7
0.2
0.0
1.0
-

0.2 to 3.4
0 to 1.1
2.9 to 2.9
0.3 to 3.5
-

5
8
2
4
1
2
8
2
2

4.5
14.3
5.4
4.9
2.4
2.5
6.5
3.1
1.8

0.8
3.5
0.0
1.0
0.0
0.0
1.4
2.6
0.3

3.3 to 7.6
6.3 to 30.9
5.4
1.9 to 6.3
2.4
2.5
2.5 to 13.2
0.5 to 5.8
1.5 to 2.2

All Major Tributaries

27.2 ± 1.6 *

16

7.4

1.5

1.9 to 30.9

18

5.1

1.3

0.3 to 23.3

1.3

0.3

0 to 3.5

34

7.0

1.1

0.5 to 30.9

Duck Creek
Goose Creek
McNeil Creek
Powerline Creek
Unnamed Creeks*

10.6
10.8
30.2
16.5
41.7 ± 13.3 *

3
2
2
2
3

3.0
4.9
5.4
5.4
1.2

0.0
0.9
1.5
0.5
0.2

2.9 to 3
3.1 to 6.2
4 to 6.9
5 to 5.9
0 to 3.5

0
1
0
0
0

5.1
-

-

-

0.1
-

-

-

3
3
2
2
3

3.0
4.9
5.4
5.4
1.2

0.0
0.9
1.5
0.5
0.2

2.9 to 3.0
3.1 to 6.2
4 to 6.9
5 to 5.9
0.8 to 1.7

All Minor Tributaries

21.8 ± 4.5 **

12

6.9

3.8

0.8 to 6.9

1

5.1

-

-

0.1

-

-

13

3.8

0.5

0.8 to 6.9

Note: Table includes position of 4 CCT for which spawning date is unknown.
* Small unnamed tributaries flowing directly into the mainstem of the Kitimat River.
** Mean ± SE

166

A1. Supplemental Recapture Information

Twelve CCT were recaptured within the Kitimat watershed. This includes four Floy
tagged and eight radio tagged CCT. The four Floy tagged (non-radio tagged) CCT were
reported by recreational anglers, two of which provided sufficient information to identify
the individual and its location of capture. The first of these two individuals, a male captured
on September 16, 2012 was recaptured 6.2 km upstream of its initial capture location on
October 6, 2012. The second CCT, a female captured on November 7, 2012 was recaptured
5.0 km downstream of its initial capture location on October 29, 2013. The two unidentified
CCT were captured by anglers who described catching trout with a yellow tag on their
dorsal fin, but did not provide the number on the Floy tag. One CCT sampled and Floy
tagged on July 22, 2013 was recaptured in the same location on July 25, 2013 and outfitted
with a small radio tag.
Four of the eight radio tagged CCT were recaptured during sampling while the
remaining four were captured and reported by recreational anglers. Radio tagged CCT
recaptured during sampling were inspected for signs of infection. Two of these fish, CCT
#003 and #051, were observed to be in poor condition. Cutthroat #003, initially captured on
August 11, 2012 was recaptured on November 16, 2012 within 500 m of its initial capture
location. This individual’s incision had closed and its sutures were intact though misplaced
and cutting through the skin. Discoloration of the skin was apparent at the exit point of the
antenna and on the abdomen where the tag appeared to be resting (Figure A1.2). Fish#003
was not observed after December 20, 2012. Fish#051 was radio tagged on October 28, 2012
and was recaptured 11.0 km downstream of its initial location on March 15, 2013. The
167

incision on this CCT appeared to have partially reopened, though no visible signs of infection
were apparent (Figure A1.3). Fish#051 was not detected after April 19, 2013, although
before this date it appeared to be moving upstream towards a presumed spawning habitat.
Fish#134 was recaptured on March 26, 2014, 21.6 km upstream of its location of capture on
July 14, 2014. This CCT appeared very healthy, it showed no signs of infection, the sutures
had dissolved and the incision had healed cleanly and was almost undetectable (Figure
A1.4). Fish#134 survived spawning and then migrated to the estuary where it was last
observed on June 28, 2014. A fourth radio tagged CCT, Fish#148 was recaptured by a
recreational angler on April 24, 2014 within 500 m of its initial capture location. Fish#148
had a 1.5 x 1.5 cm2 abscess on the outside of its abdomen, the cause of which was unclear.
The incision appears to have healed cleanly and no sutures were present (Figure A1.5). This
fish was observed in a spawning tributary from May 9 to May 12, 2014 and was last
observed in Hirsch Creek on May 27, 2014. The condition of these four recaptured cutthroat
provided insight into the condition and fate of other trout tagged throughout this study and
ultimately influenced the criteria used to identifying tagging mortalities. Due to the poor
condition of these two fish relative to the condition of Fish#134 and Fish#148, any fish that
exhibit no additional movement – regardless of the duration from their initial tagging –
were considered tagging mortalities.

168

Figure A1.2. Condition of CCT ID#3 upon recapture on November 16, 2012. Note the yellow discoloration at
the exit point of the antenna as well as on abdomen where transmitter appears to be resting. Fish was not
relocated again 1 month after this photo was taken.

Figure A1.3. Condition of CCT ID#51 upon recapture on March 15, 2013. The transmitter in this CCT was
recovered on April 19, 2013 and the fish is assumed to have died.

169

Figure A1.4. Condition of CCT ID#134 upon recapture on July 14, 2014. The incision appears to have healed
cleanly and sutures have dissolved.

Figure A1.5. Condition of CCT ID#148 upon recapture on April 24, 2014. Note that scar, circled in red has
healed cleanly. Abscess is possibly due to wear against the transmitter.

170

Chapter 2 Appendix
Table A2.1. Observations identified in scientific literature supporting the inclusion of abiotic metrics in the
overwintering candidate model set.

Variable
Discharge

Water
Temperature

Overwintering
Observation
Species and Source
Decreased flows reduce
CT: (Gresswell and Hendricks 2007)
winter movement
Decreased flows increase
Salmonid: (Jonsson and Jonsson 2002, Krimmer et
winter movement
al. 2011)
Increased flows influence
CT: (Waters 1993b, Brown and Mackay 1995a,
winter movement.
White and Harvey 2007)
Salmonid: (Enders et al. 2008)
Increased flows do not
CT: (Waters 1993b, Brown 1999, Harvey et al.
influence winter movement. 1999, White and Harvey 2007)
Salmonid: (Enders et al. 2008)
Ice formation influences
CT: (Waters 1993b, Jakober et al. 1998, Brown
winter movement
1999, Harvey et al. 1999, Harper and Farag 2004,
Lindstrom and Hubert 2004)
Salmonid: (Whalen et al. 1999, Huusko et al.
2007, Brown et al. 2011, Linnansaari 2013, Watz
et al. 2015)
Increased flows increase
CT: (Romero et al. 2005)
invertebrate drift
Decreased temperature
associated with reduced
winter movement

Decreased temperature
associated with increased
use of overwinter habitats

Movement occurs
throughout winter, even at
low water temperatures.
Increased water
temperature in spring
associated with increased
movement.

CT:(Boss 1999, Brown 1999, Harper and Farag
2004, Lindstrom and Hubert 2004, Stephan and
Zurstadt 2004, Bryant et al. 2009, Brown et al.
2011)
Salmonid:(Bustard 1970, Bustard and Narver
1975a, Jakober et al. 1998, Enders et al. 2008,
Mollenhauer 2011, Krimmer et al. 2011,
Mollenhauer et al. 2013)
CT: (Brown and Mackay 1995c, Brown 1999,
Harper and Farag 2004)
Salmonid: (Bustard 1970, Bustard and Narver
1975b, Jakober et al. 1998, Mollenhauer 2011,
Mollenhauer et al. 2013)
CT: (Stephan and Zurstadt 2004)

CT: (Waters 1993b, Stephan and Zurstadt 2004)
Salmonid: (Bustard and Narver 1975a, Jensen et
al. 1986, Swanberg 1997, Albanese et al. 2004,
Petty et al. 2012)

171

Table A2.2. Observations identified in scientific literature supporting the inclusion of abiotic metrics in the
spawning candidate model set.

Variable
Discharge

Observation
Rising flows increase
spawning movements.

Rising flows reduce spawning
movements.
Receding peak flows stimulate
spawning movements.
Decreased flows increase
spawning movement.
Variability in flows increases
variability in both the
response to flows and spawn
timing.
Turbidity increases
movement.
Water
Temperature

Increased spawning
movement associated with
rising water temperatures.

Increased spawning
movement associated with
decreasing water
temperatures.
Decreased spawning
movement associated with
cool water temperatures.
Spawning movements not
influenced by water
temperature.
Water temperature influences
spawn timing.

Source
CT: (Gresswell and Hendricks 2007, DeRito et al.
2010, Schmetterling 2011, Bennett et al. 2014)
Salmonid: (Banks 1969, Jensen et al. 1986, van
den Berghe and Gross 1989, Økland et al. 2001,
Albanese et al. 2004, Svendsen et al. 2004,
Mollenhauer 2011, Taylor and Cooke 2012,
Malcolm et al. 2012)
CT: (Brown and Mackay 1995a)
Other: (Jonsson 1991, Jonsson and Jonsson
2002, Svendsen et al. 2004)
Salmonid: (Alabaster 1990, Jonsson 1991,
Gresswell et al. 1997, DeRito et al. 2010,
Schmetterling 2011)
Salmonid: (Trepanier et al. 1996)
Salmonid: (Tetzlaff et al. 2005)

Salmonid: (Banks 1969, Alabaster 1990,
Rakowitz et al. 2008)
CT:(Gresswell et al. 1997, Stephan and Zurstadt
2004, DeRito et al. 2010, Bennett et al. 2014)
Salmonid:(Dodson and Young 1977, Jensen et al.
1986, Swanberg 1997, Albanese et al. 2004,
Svendsen et al. 2004, Petty et al. 2012)
Salmonid: (Trepanier et al. 1996, Young et al.
2010)

Salmonid: (Rustadbakken et al. 2004)

CT: (Webb and McLay 1996, Jones and Harding
1998)
CT: (Williams et al. 2009, Zeigler et al. 2012,
Kovach et al. 2013)
Salmonid: (Robards and Quinn 2002, Dahl et al.
2004, Juanes et al. 2004, Quinn et al. 2007,
Jonsson and Jonsson 2009)

172

Variable

Table A2.2 Continued
Observation

Discharge
and water
temperature

Increased spawning movement
when flow is decreasing and
temperature is increasing.

Photoperiod

Day length is proximate factor
indicating migration season
Day length influences motivation
to spawn.
Day length influences rheotropic
behaviour.
Day length acts as cue for
physiological changes

References

CT: (Gresswell and Hendricks 2007)
Salmonid: (Swanberg 1997, Svendsen et al.
2004, Ringel et al. 2014)

Salmonid: (Smith 1985)
Salmonid: (Banks 1969, Jonsson 1991,
Thorstad et al. 2005, 2008)
Salmonid: (Dodson and Young 1977,
Smith 1985)
Salmonid: (Macquarrie et al. 1978,
Whitehead et al. 1978, Smith 1985,
Carrillo et al. 1989, Fleming 1996,
Norberg et al. 2004, Garcia de Leaniz et
al. 2007)

Sex

Sex influences timing of
migrations

CT: (Jones and Yanusz 1998)
Salmonid: (Morbey 2000, Dahl et al.
2004)

Fork Length

Size influences timing of
spawning movements

CT:(Jones and Yanusz 1998, Young 2011)
Salmonid: (Swanberg 1997, Curry et al.
2002)
CT: (Alexiades et al. 2012)

Size does not influence
movement timing.
Size influences distance travelled.
Size does not influence distance
travelled.
Distance to
Spawn

Increased distance to spawn
decreases date.

Salmonid: (Wenger et al. 2011)
Salmonid: (Svendsen et al. 2004)

Salmonid: (Bahr and Shrimpton 2004)

173

Table A2.3. Mean water temperature recorded in tributaries of the Kitimat river throughout the overwinter period (October 1 to March 14), spawning period
(March 15 to May 31) and combined periods (October 1 to May 31) of each year.

Year

Tributary

Deployment Date

1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
2
2
2

Hirsch
Cecil
Nalbeelah
Little Wedeene
Humphrey
McNeil
Big Wedeene
Chicken
Goose
Lone Wolf
Hirsch
Chist
Cecil
Nalbeelah
Little Wedeene
Humphrey
Duck
Chicken
Big Wedeene
Deception
Goose
McNeil

1-Oct-12
1-Oct-12
6-Oct-12
1-Oct-12
1-Oct-12
18-Dec-12
1-Oct-12
12-May-13
24-Apr-13
23-Oct-13
1-Oct-12
12-Oct-13
1-Oct-12
6-Oct-12
1-Oct-12
1-Oct-12
11-Oct-13
12-May-13
1-Oct-12
17-Oct-13
24-Apr-13
18-Dec-12

Winter
(Oct. 1 to March 14)
Mean
SD Range

Spawn
(March 15 to May 31)
Mean
SD Range

Combined
(Oct 1 to May 31)
Mean
SD Range

1.8
1.6
1.8*
1.9*
2.7
1.7*
2.9
1.6*
2.3
2.2
2.2
2.6*
2.4
2.9
2.6*
2.9*
3.1
2.1*
2.6
5.4

3.1
3.7
3.6
3.5
3.4
4.7
4.1
7.2*
9.1*
3.9
2.9
3.8
3.9
3.1
3.8
3.3
3.9
4.0
3.9
5.8
5.5
3.9

2.2
2.3
2.4*
2.4*
2.9
3.1*
3.3
7.2*
9.1*
2.4
2.5
2.7
2.8
2.8
2.8
3.0
3.1*
3.3*
3.4
3.4
3.5
5.2

1.9
1.9
1.9
1.9
1.7
0.9
1.7
1.7
2.6
2.1
2.2
2.7
2.4
2.1
2.4
2.8
2.1
2.4
2.9
2.0

0 - 8.3
-3 - 6.6
-0.1 - 8.1
0-8
0.2 - 8.6
0.1 - 3.4
0.3 - 9
0 - 7.5
0 - 8.2
0 - 7.7
-0.1 - 7
0.1 - 8.6
0 - 8.1
0.1 - 7.8
0 - 8.9
0 - 9.1
0.3 - 8
0.1 - 9.1
0 - 9.4
0.5 - 9.8

1.0
1.2
1.1
0.9
1.0
1.4
1.2
0.9
2.2
2.2
1.4
1.6
1.3
1.5
1.4
1.5
1.8
2.5
1.6
3.9
3.8
0.7

0.6 - 4.9
-0.3 - 6
0.6 - 5.4
1.2 - 5.4
1.8 - 5.8
1.6 - 7.6
2.4 - 6.7
6.1 - 8.5
5.3 - 12.1
0.1 - 7.5
0.2 - 5.5
0.7 - 6.8
0.6 - 6.6
0.6 - 6
0.8 - 6.9
0.2 - 6.1
0.5 - 7.4
0.7 - 8.4
0.5 - 6.7
0.1 - 12.1
0.1 - 11.4
2.6 - 4.8

1.8
2.0
1.9
1.8
1.5
1.9
1.6
0.9
2.2
2.2
2.3
2.1
2.1
2.4
2.2
1.9
2.3
2.8
2.0
3.5
3.5
2.0

0 - 8.3
-3 - 6.6
-0.1 - 8.1
0-8
0.2 - 8.6
0.1 - 7.6
0.3 - 9
6.1 - 8.5
5.3 - 12.1
0 - 7.5
0 - 8.2
0 - 7.7
-0.1 - 7
0.1 - 8.6
0 - 8.1
0.1 - 7.8
0 - 8.9
0 - 9.1
0.3 - 8
0.1 - 12.1
0 - 11.4
0.5 - 9.8

* Indicates that temperatures were not collected throughout the entire period.

174

Table A2.4. Summary of date that radio tagged CCT were first observed in spawning tributaries and the temperature of spawning tributaries upon arrival.

Date
Tributary

Year

n

Median

SE

Range

Big Wedeene
Cecil
Chicken
Chist
Deception
Duck
Goose
Hirsch
Humphrey
Little Wedeene
Nalbeelah
Big Wedeene
Cecil
Chicken
Chist
Deception
Duck
Goose
Hirsch
Humphrey
Little Wedeene
McNeil
Nalbeelah

1
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
2
2

5
4
3
2
1
1
3
1
0
1
1
3
4
2
0
1
2
1
0
1
1
0
3

20-Apr
9-Apr
20-Apr
28-Apr
17-Apr
18-Apr
3-Apr
23-Apr
4-May
1-Apr
2-May
11-Apr
3-May
6-Apr
23-Apr
23-Apr
30-Apr
27-Apr
28-Apr

8.23 07-Apr to 04-May
8.51 26-Mar to 23-Apr
5.34 12-Apr to 29-Apr
0.71 28-Apr to 29-Apr
NA
17-Apr to 17-Apr
NA
18-Apr to 18-Apr
1.87 01-Apr to 06-Apr
NA
23-Apr to 23-Apr
NA 04-May to 04-May
NA
01-Apr to 01-Apr
1.00 01-May to 03-May
3.03 07-Apr to 16-Apr
2.45 30-Apr to 07-May
NA
06-Apr to 06-Apr
0.71 23-Apr to 24-Apr
NA
23-Apr to 23-Apr
NA
30-Apr to 30-Apr
NA
27-Apr to 27-Apr
1.29 27-Apr to 30-Apr

Water Temperature ( °C)
Mean
SD
Range
3.63
3.71
n/a
n/a
n/a
n/a
6.28
3.75
3.63
3.31
4.37
3.44
3.65
3.78
3.82
5.44
3.8
4.95
3.7
3.44
3.49
n/a
4.08

0.58
0.71
n/a
n/a
n/a
n/a
1.05
0.57
0.58
0.56
0.55
0.86
0.93
1.13
0.92
2.12
1.01
2.38
0.89
0.86
0.91
n/a
1.05

2.85 to 5.24
2.52 to 5.62
n/a
n/a
n/a
n/a
5.26 to 8.47
2.78 to 5.33
2.85 to 5.24
2.2 to 4.58
3.28 to 5.92
1.19 to 5.01
1.1 to 5.27
1.94 to 6.17
1.6 to 5.54
1.4 to 9.24
1.58 to 5.35
0.97 to 9.41
1.55 to 5.25
1.19 to 5.01
1.21 to 5.18
n/a
1.72 to 5.68

175