For the third straight year, the Oregon and Washington fish and wildlife departments are hazing sea lions to deter them from preying on runs of threatened salmon and steelhead below Bonneville Dam on the Columbia River.
Using non-lethal deterrents such as crackershells, rubber buckshot and underwater firecrackers, crews will be working from boats seven days per week through May 31 in an effort to drive the marine mammals away from fish congregated below the dam. The hazing area extends six miles downstream from the dam to Marker 85.
“As in previous years, our goal is to change these animals’ behavior,” said Jeff Koenings, director of the Washington Department of Fish and Wildlife (WDFW). “Predation by sea lions on fish in the tailrace of Bonneville Dam is a fairly recent phenomenon, and we don’t want any more of them to learn that behavior. We want them to recognize that this is not a good place to find an easy meal.”
Like last year, WDFW and the Oregon Department of Fish and Wildlife will conduct the hazing in cooperation with the National Marine Fisheries Service (NMFS) – the agency that is funding the ESA salmon/steelhead protection effort – the U.S. Department of Agriculture Wildlife Services Program, Columbia River Inter-Tribal Fish Commission and the U.S. Army Corps of Engineers, operators of the dam.
Hazing methods will remain the same as last year, but this year’s seven-day-per-week schedule marks a significant escalation in the effort to deter predation by sea lions, said Sandra Jonker, regional WDFW wildlife manager.
“We want to give non-lethal deterrence every chance to succeed,” Jonker said. California sea lion numbers have burgeoned since the 1970s. A September wildlife survey by WDFW documented 1,200 California sea lions at the mouth of the Columbia River, among an estimated West Coast population of 300,000 animals.
Despite previous hazing efforts by Oregon and Washington in 2005 and 2006, the number of sea lions entering the Columbia River – and their rate of predation on ESA-listed salmon and steelhead below Bonneville Dam – has increased significantly since 2001, according to surveys by the U.S. Army Corps of Engineers.
Estimated predation on salmon and steelhead immediately below Bonneville Dam has reached over 3 percent of the total upriver run in some years, according to surveys conducted by the Corps.
“In addition to the impact on salmon and steelhead, we remain very concerned about the predation on the white sturgeon,” said Charlie Corrarino, ODFW Conservation and Recovery Program Manager. “Broodstock male and female sturgeon are being preyed upon at an alarming rate.”
In February, for the second year, Oregon and Washington conducted a separate state-funded hazing campaign designed to protect those slow-maturing fish, some of which can carry as many as three million eggs.
But the primary focus of the current hazing effort is to protect migrating salmon and steelhead, many of which are listed for protection under the federal Endangered Species Act. Upper Columbia River spring chinook are listed as “endangered” under the ESA; lower Columbia River chinook and steelhead, middle Columbia River steelhead, Snake River spring/summer chinook, and Snake River Basin steelhead are all listed as “threatened.”
Concerned about predation on those populations, fish managers in Oregon, Washington and Idaho jointly applied last November to NMFS for permission to use lethal means – if necessary – to remove individual California sea lions that prey on chinook salmon and steelhead below Bonneville Dam.
The application was submitted under Section 120 of the Marine Mammal Protection Act, which allows lethal removal of individual pinnipeds that negatively impact federally protected salmonid stocks.
NOAA Fisheries is soliciting public comments on the states’ application through April 2.
“In the meantime, we need to do everything we can to protect our fish resources,” Jonker said.