There are factors that we can point to. One element we particularly care about these days is the impacts of climate change as it affects temperature and flows in the river. You have marine issues around the types of feed available for the salmon. You also have the impacts on the rivers as the salmon return. It is thus a complex issue. It's one that requires more science to really understand, and those are some of the investments we're making in the species.
On May 4th, 2017. See this statement in context.