Genetic variation in mortality of chinook salmon,Oncorhynchus tshawytscha(Walbaum), challenged with high water temperatures

摘要

Abstract.Chinook salmon,Oncorhynchus tshawytscha(Walbaum), from a northern streamtype (Bear River) and a southern ocean‐type (Robertson Creek) population in British Columbia were mated within populations in a nested breeding design and the resulting juveniles were challenged with high water temperatures. Juveniles in the southern population died significantly later than those in the northern population, but none of the variation among families in mortality rate or time to death in the southern population was attributable to additive genetic variation. Non‐additive genetic or maternal effects or both were observed for mortality rates in the Robertson Creek population, whereas additive genetic effects were observed for mortality at temperatures less than 22°C in the Bear River population. Larger fish survived better during the challenges than did smaller fish, and there was a negative genetic correlation (based on dam variance components) between body weight and morta