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Latest Bi-Weekly Pinniped Report Shows
Decline in Steller, California Sea Lions at Bonneville Dam

by Staff
Columbia Basin Bulletin, June 1, 2018

Ted Walsey, fishery technician for Columbia River Inner Tribal Fish Commission, fires a cracker shell towards a sea lion, during routine hazing on the Columbia River near the Bonneville Dam (Ariane Kunze / Columbian) While the number of California sea lions in the Bonneville Dam tailrace continues at a below average pace, Steller sea lion numbers are above the 10-year average (2008-17).

Still, numbers of sea lions have declined, according to the latest bi-weekly report released last week by the U.S. Army Corps of Engineers, and so have the numbers of salmon and steelhead the sea lions snack on in the tailrace of the dam.

The fourth pinniped report of sea lions and predation at the dam was released last week by the Corps for the period May 11 to May 24. The report was prepared by Kyle Tidwell of the Corps' Fisheries Field Unit.

Sea lion numbers, both Steller and California sea lions, have varied in each of the four reports since the Corps released its first bi-weekly report on their presence April 12. The latest pinniped abundance information from the fourth bi-weekly report showed an average daily abundance of Steller sea lions at the dam of 19.7, whereas the average daily abundance for California sea lions observed during the period was 8.5.

That is lower than the previous bi-weekly report that showed an average daily abundance (April 26 - May 10) of 51.5 Steller and 10.1 California sea lions.

The first report of the year showed an average daily abundance of Steller sea lions of 7.7 and 0.4 California sea lions. The second report, released April 26, reported an average daily abundance of Stellers of 26.8 and California sea lions of 4.3.

In previous years, California sea lions have typically outnumbered Steller sea lions. No harbor seals have been observed since January 24.

Some 54 Steller sea lions were observed on May 11 during the period May 11 - May 24 and as many as 12 California sea lions were observed.

The Corps documented 27 Steller and 39 California sea lions as uniquely identifiable individuals during the most recent period. All uniquely identifiable sea lions have been documented near Bonneville Dam in previous years, except two California sea lions which were branded and released. The low number of individually identifiable Stellers is due to the limited branding effort for the species.

Observed predation by sea lions from May 11 to May 24 is lower at 178 spring chinook, five steelhead and three white sturgeon. Steller sea lions took 91 of the chinook, four steelhead, three sturgeon, five lamprey and nine unknown fish. California sea lions took 87 chinook, one steelhead, two lamprey, two other types of fish and 19 unknown.

Some 611 spring chinook were taken April 26 - May 10, along with 26 steelhead and five white sturgeon. Of the total 718 recorded predation events for all fish, Steller sea lions accounted for 82 percent of them.

Since 2008, Oregon Department of Fish & Wildlife and Washington Department of Fish & Wildlife have staffed a branding and removal program for California sea lions. According to a Section 120 report from ODFW to NOAA Fisheries under the Marine Mammal Protection Act, one California sea lion was euthanized May 15.

Weekly Section 120 reports to NOAA are here.

A bill introduced in Congress by two members of the Northwest's congressional delegation one year ago in April would make it easier for tribes and states to obtain permits to remove sea lions from the Bonneville Dam tailrace.

The Endangered Salmon and Fisheries Predation Prevention Act would allow both tribes and states to remove sea lions near Bonneville Dam. While the removal program as proposed by the bill would still be subject to and limited by Section 120 of the Marine Mammal Protection Act, it would more closely be brought into alignment with the Endangered Species Act, according to the Columbia River Inter-Tribal Fish Commission.

Introduced by U.S. Reps. Jaime Herrera Beutler (R-WA) and Kurt Schrader (D-OR), the bill would allow Northwest states and tribes to potentially obtain sea lion removal permits via an expedited process.

In addition, ODFW applied for a Section 120 permit last year to lethally remove California sea lions at Willamette Falls, some 12 miles upstream from Portland on the Willamette River.

Related Pages:
Falling Prey by Eric Barker, Lewiston Tribune, 5/20/18
Hazing Sea Lions Not a Long-term Fix by Dameon Pesanti, The Dalles Chronicle, 5/11/18
Bill Would Streamline Process to Kill Sea Lions Near Bonneville Dam by Brian Brennan, KGW8, 4/4/18
'We're Losing' Sea Lion Fight by Dameon Pesanti, Spokesman-Review, 4/5/18
Sea Lions Focus of Fish Survival War by Gillian Flaccus, The Dalles Chronicle, 3/22/18

Latest Bi-Weekly Pinniped Report Shows Decline in Steller, California Sea Lions at Bonneville Dam
Columbia Basin Bulletin, June 1, 2018

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