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Pelicans compete with gulls to search for fish scraps on the Pacific Seafood Company dock in Newport. As Oregon's pelagic fish move northward in search of cooler waters, birds that rely on them for food could be affected, too.

(Doug Beghtel/The Oregonian)

Clarification appended.

Climate change is expected to push some of Oregon’s most abundant fish species northward in the next 35 years, producing potentially damaging effects for Oregon’s commercial fisheries.

Scientists from the National Oceanic and Atmospheric Administration and the University of British Columbia on Wednesday released a first of its kind look at future projections of species shift caused by warming oceans. They found that pelagic fish – those that tend to dwell closer to the ocean's surface – will seek cooler waters as the southern end of their habitat heats up.

In Oregon, salmon and hake – two important commercial fish – could begin to abandon the waters off Newport and Astoria, and become more abundant in places further north. Brodeur noted that hake weren't included in this specific study.

“If fishers want to stay with these fish, they’ll need to move farther north,” said Richard Brodeur, a Newport-based NOAA scientist who co-authored the study.

The report, published in the journal Progress in Oceanography, estimates that ocean temperatures up and down the West Coast will rise up to five degrees Fahrenheit within the next 35 years.

“That doesn’t seem like much, but fish often have a very narrow temperature range,” Brodeur said.

Marine species migration is a global trend, happening in fisheries from New England to Australia. Fish typically found closer to the equator have begun moving toward the poles, pushed out of their typical habitat by warming oceans.

Of the 28 species of West Coast fish the NOAA team studied, all will migrate north if current trends in greenhouse gas emissions continue.

The migration could impact more than just the commercial fishing industry. Seabirds and ocean mammals depend upon the same fish for food. If their primary food moves north, Brodeur said, “like fishermen, they’re going to have to go farther to find food, or find another food source.”

In Oregon the northward shift is already visible.

Take, for instance, albacore tuna. Formerly a California fish, albacore is now more common in Oregon and Washington. Brodeur and his team expect the trend to continue.

In some cases, that migration could create new opportunities for fishermen whose preferred catch is expected to seek cooler waters. But Brodeur said it could also mean a return of potentially damaging species like the Humboldt squid, a “voracious predator” typically found near Mexico.

The temperature shift isn’t expected to be as strong at deeper ocean depths, Brodeur said. That could create imbalances in the food chain if pelagic fish that typically feed on deeper-dwelling species abandon the region.

“It’s kind of scary, but at the same time I think we need to know about these things,” he said. “Fortunately, it’s going to be a gradual transition so we have time to adapt.”

Clarification: Although hake are expected to shift north as waters warm, they were not included in this study.

-- Kelly House