In several populations of pink salmon, the short-term dynamics population size was related to both the mean and variance of individual family sizes, because not all families were equally productive. In the marine lifestage, population increases came disproportionately from the most productive families, especially in populations with the highest average marine survival. Moreover, the trait of marine survival itself had a statistically detectable genetic component. This implies that the most favored phenotypes change from generation to generation, and that the marine environment is unpredictable and changing. These results, together with laboratory studies of freshwater survival and measurements of wild pink salmon in Prince William [...]
