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Report: Willamette Steelhead near extinction from feasting sea lions

Sea lions hang out near Willamette Falls near Oregon City. They eat fish in the river. (KATU Photo)

SALEM, Ore. – Steelhead trout living in the Willamette River are facing extinction because sea lions are eating the fish as they head upriver to spawn, a new Oregon Dept. of Fish & Wildlife (ODFW) report said.

The number of steelhead running upstream through Willamette Falls is at an all-time low, with only 512 fish making it above the falls since January 1.

Researchers say that sea lions are eating about a quarter of the wild winter steelhead run while they congregate below the falls. If the predators continue to hunt the fish at those levels, the report says there’s a 90 percent chance one of the upriver populations will go extinct.

Researchers analyzed the chances of extinction within the next 100 years on four tributaries upstream from Willamette Falls: North Fork Santiam, South Fork Santiam, Calapooia, and Molalla. Steelhead populations on the Calapooia appear to be most at risk. Without sea lions, the chances of steelhead extinction on the other three rivers is near zero, but increase significantly if sea lions continue to take as many fish as they did in 2017.

Department officials said they need to take immediate action to limit the sea lion access to Willamette Falls if they want to avoid steelhead extinction.

“We know what the problem is and have seen this coming for about a decade, we just couldn’t take action to prevent it,” said Dr. Shaun Clements, a senior scientist with ODFW.

Back in June, the state applied for a permit to capture and euthanize sea lions – which are protected under the federal Marine Mammal Protection Act. Clements says permits take a long time to process, an act of congress may be needed to help the steelhead even sooner.

Two local members of congress, Jaime Herrera Beutler and Kurt Schrader, sponsor a bill known as Endangered Salmon and Fisheries Predation Prevention Act. It would amend the Marine Mammal Protection Act to reduce sea lion hunting on Columbia and Willamette Rivers.

Others aren't so quick to blame the sea lions. Conrad Gowell, River Steward Program Director with Native Fish Society, says sea lions will play a role, but there are a range of factors which have contributed to steelhead trout decline over several decades.

"Sea lions, no question, do have an effect on wild winter steelhead, but I wouldn't pin the extinction of steelhead on sea lions. The network of habitats and environmental conditions have been declining for the past 100 years," Gowell said.

Steelhead populations have been declining for decades. Habitat loss, dams preventing fish passage, harvesting while steelhead spawn, and other factors are known to contribute to the decline. This year, low numbers are being attributed to poor ocean conditions and a drought in 2015.

The issue of sea lions hunting during migration is not a new problem for the vulnerable salmon and steelhead populations in the Pacific Northwest.

Over the past four decades, California sea lions have expanded up the West Coast. Officials said a small portion of the male sea lions have started venturing into freshwater territory. Clements says they have to figure out how to balance conservation of sea lions with steelhead salmon on the Willamette.

“Removal of a few problem individuals will have no impact on the overall sea lion population, but can significantly benefit ESA-listed fish,” said Robin Brown, lead scientist for ODFW’s marine mammal program.

Officials said any action to help the salmon and steelhead populations would also consider the conservation of sea lion populations. There are currently around 300,000 sea lions coast-wide, ODFW said.

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