Influence of temperature on incubation rates of coho salmon (Oncorhynchus kisutch) from ten Washington populations

Coho salmon from 10 Washington populations were incubated under controlled conditions to determine the levels of variation in time to hatch among populations and families within populations. The average incubation rate was somewhat slower than that estimated from a quantitative model derived from British Columbia populations, and was slightly faster than that predicted by a Washington model. Significant variation in incubation rated among the Washington populations was detected, consistent with results from other studies. Data of first hatching of families within populations ranged more than two weeks at 6°C. Within families, the first and last individuals to hatch ranged over 1-3 weeks. The variation within populations and families will contribute to the variation in emergence date of fry, which will affect their growth and survival.