Yet it turns out the salmon were feeding more than their own young, they were feeding the whole neighborhood. Salmon really are a keystone species. Willson and Halupka put forward that idea years ago, but we're just now thinking through what that really means. For example the reestablishment of the grizzly bear may be impeded by not having the primary food source it evolved with. The abundance of all these things is interrelated.
Many insects feed on salmon, and then become food for juvenile salmon.
No less than 82 species feed directly on salmon carcasses. Pacific salmon are the food base for much of what lives in the watershed. When the salmon disappear, stark examples of their importance can be seen. Cederholm points to the example of McDonald Creek in Glacier National Park. In 1981 more than 600 bald eagles gathered to feed on kokanee salmon carcasses, Cederholm said.