It is certainly true that, in trying to understand the multitude of factors that affect Pacific salmon populations, it is a complex picture, and we know that there are multiple factors that positively influence the returning populations of Pacific salmon. Certainly, that's one reason we conduct the diet composition studies for pinniped populations, but it's also why we invest time and energy into pathogen studies, habitat studies, monitoring the returns throughout the north Pacific climate change study, etc. We have such diverse Pacific salmon research programs to try to understand the multiple factors that affect their survival.
On March 9th, 2023. See this statement in context.