Pinniped Predation on Chinook Salmon

Using molecular scatology to determine winter and spring pinniped predation on Chinook salmon in Northwest Washington: Implications for salmon recovery, fisheries management, and endangered Southern Resident Killer Whales

Researchers used molecular scatology and quantitative models to advance understanding of how winter and spring pinniped predation on Chinook salmon in Northwest Washington affects salmon recovery and Southern Resident Killer Whales.

Principal Investigator

Adrianne Akmajian, Makah Tribe, Makah Fisheries Management

Co-Principal Investigators

Alejandro Acevedo-Gutierrez, Western Washington University

Dietmar Schwarz, Western Washington University


Researchers expanded current knowledge about pinniped and salmonid predator-prey dynamics by analyzing the predation habits of harbor seals (Phoca vitulina) and Stellar sea lions (Eumetopias jubatus). They focused on an understudied time and region: winter and spring off the northwest Washington coast and western Strait of Juan de Fuca. The research team collected data on pinniped diet including salmonid species consumed, age class, and biomass by using scat analysis, molecular techniques, and quantitative models. They also documented pinniped sex to determine if sex-biased predation exists. Understanding pinniped predation is key in salmon management, and the results informed how pinnipeds compete for salmonids with fisheries and endangered Southern Resident Killer Whales.