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Warmer water brings big, exotic species into the Salish Sea

A bluefin tuna washed ashore on Orcas Island in July 2023.
Joe Gaydos
SeaDoc Society
A bluefin tuna washed ashore on Orcas Island in July 2023.

Marine heat is causing some unusual species to show up in Puget Sound and the Salish Sea. Recent reports include two sightings in August of six-foot-long sunfish near Tacoma, Wash. Also recently seen: a huge bluefin tuna in the San Juan Islands.

It may be impressive, but it’s not all that surprising that people are starting to see these exotic species in the Northwest, said Elliott Hazen with NOAA Fisheries Southwest Science Center. He told KNKX they respond to ocean temperatures and they follow their preferred prey. He co-authoreda new paper on how marine heat affects the distribution of apex predators.

"The real question is, when does it you know, when does it become the new normal?" Hazen said. "Are we going to be seeing sunfish every year now in Puget Sound? And maybe that's a cool tourism opportunity. Bluefin tuna in San Juan Islands, you know, are we accounting for that in our tourism or fisheries management as well?"

Bluefin is the largest species of tuna – extremely valuable as a commercial crop.

Hazen said it’s possible that these sightings are still anomalies. He added that "citizen science data" provides an important metric for such events. NOAA Fisheries is encouraging people who use social media to follow the agency and report any unusual marine life they see, to help researchers track the changes.

NOAA Fisheries spokesperson Michael Milstein said while this is not unprecedented, it is unusual and has everyone asking - why?

“The answer appears to be that the ocean off the West Coast has warmed quite dramatically in the last couple of months as a major marine heatwave has kind of moved up against shore," Milstein told KNKX. "And so the species are finding their preferred temperatures in a lot larger area, including, now, Puget Sound.”

He said these larger species serve as sentinels of what’s changing in the entire ecosystem because they chase their preferred prey. Bluefin tuna follow anchovies. Sunfish – also known as Mola Mola – go after certain kinds of jellyfish.

Hazen said while the uncertainty is frustrating, scientists now have predictive tools to help them visualize the heat waves and assess how it may impact the ecosystem.

"We're very heavily trying to monitor and understand," Hazen said.

Updated: September 13, 2023 at 1:56 PM PDT
Added image and additional reporting.
Bellamy Pailthorp covers the environment for KNKX with an emphasis on climate justice, human health and food sovereignty. She enjoys reporting about how we will power our future while maintaining healthy cultures and livable cities. Story tips can be sent to