There are no known new technologies, and the methods now used in attempts to chase California sea lions away from their salmon feeding grounds below Bonneville Dam lack effectiveness.
So the Pinniped-Fishery Interaction Task Force is considering a recommendation that hazing not be a precondition for the lethal removal of the marine mammals as a means to reduce predation on salmon and steelhead stocks that are listed under the Endangered Species Act.
A federal letter of approval granting the states of Idaho, Oregon and Washington lethal removal authority says that California sea lions must be “subjected to active non-lethal deterrence” before a lethal solution is implemented. And the statute that allows lethal removals, Section 120 of the Marine Mammal Protection Act, says the task force must “suggest nonlethal alternatives, if available and practicable, including a recommended course of action.”
The task force was formed in 2007 by NOAA Fisheries Service to consider whether the states’ application for lethal removal authority should be approved. The panel was reconvened this week to evaluate the program’s effectiveness to date at reducing salmon predation and, potentially, make recommendations about how the program’s effectiveness might be improved.
The hazing was used before lethal removal was authorized in March 2008 and seems only to move the animals, not reduce predation or chase them downriver, according to research.
The U.S. Department of Agriculture’s Wildlife Services has used various non-lethal deterrents, working from the dam face in observation areas of Powerhouse 1, the spillway and Powerhouse 2, dawn to dusk, seven days per week during the March-May period. That effort is coordinated with boat-based hazing by carried out by the Oregon and Washington departments of fish and wildlife and the Columbia River Inter-Tribal Fish Commission.
The hazing has involved a combination of acoustic, visual, and tactile non-lethal deterrents, including vessel chasing, above-water pyrotechnics (cracker shells, screamer shells or rockets), rubber bullets, rubber buckshot, and beanbags. Boat-based crews also used underwater percussive devices known as seal bombs.
But, the states and CRITFC say the hazing has been largely futile, as does U.S. Army Corps of Engineer researchers who monitor the sea lions presence at Bonneville, and their feeding activity.
“Harassment efforts continued each year both from land and boats and continue to show limited local, short term benefits in chasing some sea lions away from fishways and tailrace areas. Acoustic deterrents have shown no impact at all to the presence of sea lions near the fishway entrances,” according to the Corps researchers’ “Evaluation of Pinniped Predation on Adult Salmonids and Other Fish in the Bonneville Dam Tailrace, 2008-2010.”
“For all years, hazing activity temporarily moved some sea lions out of tailrace areas, but the animals typically returned and resumed foraging shortly after hazer’s left the area,” the report said. And the animals appear to have made up for that lost time.
“A slight shift to more predation occurring in the first and last hour of light during the day can be seen, which corresponds to hazing activities start and end times.
“The high adult salmonid and sturgeon consumption estimates seen in 2010 suggest that, at best, hazing at the current level of intensity only slows the increase of predation,” the report says.
The dam-based hazing is non-negotiable, since is to a large extent put in place by the U.S. Army Corps of Engineers to deter avian predators that gather to feed on juvenile salmon headed downstream. The sea lions’ primary focus is spring chinook salmon spawners. The Corps operates the dam.
Steve Williams of ODFW and Guy Norman of WDFW, both task force members, suggested that the rules be changed so that hazing could be used on-call to address specific situations – such as to chase protected Steller sea lions off the floating traps to make room for California sea lions – but not be required. That would allow funds now spent on hazing to be shifted to other purposes that might be more helpful.
Doug Hatch, a Columbia River Inter-Tribal Fish Commission biologist, agreed that more flexibility is needed and that at least some of the hazing money could be put to better uses.
“It would give us an opportunity to do more of the acoustic telemetry, track the animals” to learn more about their activity and about the sea lions’ abundance elsewhere, said Hatch, also a task force member.
“It’s expensive,” Hatch said of a tribal effort that involves a boat and three people five days per week for three months.
“But you can’t just cut it off,” Hatch said. The hazing has helped to some degree shooing Steller sea lions, which plunder white sturgeon that congregate just below the dam in winter. Any shifting in funds would have to involve discussions with the Bonneville Power Administration, which funds the CRITFC hazing effort.
The states too want protections for white sturgeon, which are a valued resource for anglers and commercial fishers alike. But it appears the Stellers, like their California cousins, have become immune to the hazing.
“It’s moving them around but not out of the area,” Williams said, adding that his definition of effectiveness is “getting them out of there.”
Task force member Daryl Boness, Marine Mammal Commission member, suggested that perhaps the hazing could be scaled up to a level involving chasing the animals farther downstream, rather than scaled down.
But Brian Brown, head of the ODFW’s Marine Mammal Project, said that had been tried but the area is just too big “and there are fish everywhere” for the animals to prey on. The animals would flee downriver, “but in an hour they’re back. You just can’t do that all day long.”
Williams said he was not suggesting that hazing be ended but rather that those involved be allowed “to use the tool when they feel it is most necessary” to support the goal of reducing predation.
The Human Society of the United States’ Sharon Young said that Section 10 requires that non-lethal means must be proven ineffective before they could be ended. So far the hazing has not produced the desired result – chasing animals away from the dam – but has likely had some effect reducing predation, she said.