Spawning site selection and the influence of incubation environment on larval success in interior Fraser coho.

Habitat features have been shown to influence salmonid spawning site selection as well as the survival and growth of larval fish throughout incubation. Most studies have been conducted in coastal watersheds, however, and little is known regarding habitat features associated with spawning sites for interior populations of salmon. My study examined factors affecting spawning site selection and incubation success for a population of interior Fraser coho salmon (IFC) (Oncorhynchus kisutch), in McKinley Creek watershed, British Columbia. Ground surveys coupled with radio telemetry were used to identify spawning site locations. An information theoretic approach was used to examine the probability of spawning site use based on habitat features. Incubation of larval fish within in-stream artificial redds allowed for the assessment of survival and growth in different incubation environments. The spawning habitat use of IFC throughout the McKinley Creek watershed was more extensive than previously realized. Hyporheic conductivity, dissolved oxygen, temperature and specific discharge were the best indicators of spawning site selection. Despite significant differences in habitat variables between used and unused spawning sites, survival and growth of larval IFC did not differ between sites maternal effects were greater than incubation habitat features. This study has provided critical information about spawning site selection and the incubation environment of IFC, and has contributed to the understanding of the influence of habitat features on salmonids in interior watersheds.