Salmon predation has become a major factor up and down the Pacific coast and is not limited to rivers or dams. Protections put into place for birds and marine mammals have allowed these salmon predator populations to expand in the past few decades. To support their greater numbers, salmon predators, such as sea lions, have invaded areas where they weren’t previously observed, including rivers. To help counter this problem, anti-predation programs are in place to protect salmon. Still, predation remains an area where more work needs to be done.

Encyclopedia of Puget Sound – Study says predators may play major role in chinook salmon declines
Protecttheharvest.com – news
Govtrack.us “Endangered Salmon and Fisheries Predation Prevention Act”