Chinook Salmon an Increasingly Popular Food Choice of Sharks

Chinook salmon. File photo.

Wild Chinook salmon, a perennial favorite of seafood aficionados at upscale restaurants, is also becoming increasingly popular with a tough and hungry predator found in ocean waters from the Central Bering Sea to the coast of Oregon.

“Predation by salmon sharks is on the increase,” Andrew Seitz, a researcher at the University of Alaska College of Fisheries and Ocean Sciences, in Fairbanks, Alaska, said. “We don’t know how long because we haven’t been doing this long enough, but signs are (that) there are a lot of them out there in the ocean.”

Seitz presented his research findings on the decline of Chinook salmon abundance in the North Pacific Ocean during the Gulf of Alaska plenary session of 2025 Alaska Marine Science Symposium in Anchorage on Jan. 28.

“The ocean is a dangerous place for Chinook salmon,” he said. “Salmon sharks are warm blooded and because of that they have a very high metabolism, (they can weigh) to 300 to 400 pounds and can eat a lot of fish.  We don’t know what portion of their diet is Chinook salmon.”

Seitz, with colleagues Hannah Myers of Oregon State University and Michael Courtney, of the University of Alaska Fairbanks, is engaged in an ongoing study funded by the U.S. Navy on late-marine Chinook salmon.

The trio plan to publish their current findings in a research peer journal, he said.

Currently a petition is being reviewed to list Gulf of Alaska Chinook salmon as threatened or endangered under the Endangered Species Act. While multiple factors likely drive these declines, recent research has highlighted the potential importance of late-marine stage mortality.

Their work to date leveraged a 10-year data set from satellite archival tags which showed that 42 of 199 tagged kings were eaten by salmon sharks.

Since 2013 they have been attaching satellite tags to salmon. They have tagged Chinooks from the north Central Bering Sea to Craig, in Southeast Alaska. During 2025 they plan to go back to Craig to tag 24 more kings and then another 15 kings in the Southeast Bering Sea, through a collaborative project with the Alaska Department of Fish and Game.

Salmon sharks aren’t the only ocean critters with a yen for those Chinooks, Seitz said. Killer whales, Steller sea lions and pelagic fish, like blue sharks, which are becoming increasingly common in Southeast Alaska waters. Satellite tags are used to study these fish, to understand their behavior, he said.

Tagging began in 2013 to study the behavior of king salmon, to see if they could predict where and when the Chinooks would be in the ocean. The eventual goal is to use the predictions to help the pollock industry reduce Chinook bycatch in the pollock fishery.

The study demonstrated that the many agents of mortality on late-marine Chinook salmon are related to region and fish. The information is useful for informing population dynamics models and understanding changes in Chinook salmon demographics, including size and age structure, the researchers said.