California sea lions, which have throughout time plundered commercial fish nets and stole fish from anglers’ lines in the lower river, have expanded their range.
At least three, and maybe four, of the big marine mammals this year have managed to find their way above Bonneville Dam, the lowermost hydro project on the Columbia River (146 river miles from the Pacific).
The animals are believed to have passed upstream through the dam’s navigation locks. One story, though not validated, is that one sea lion was seen riding a shipping barge through the locks at the dam, according to Stuart Ellis, a fishery biologist for the Columbia River Inter-Tribal Fish Commission.
As the story goes, U.S. Army Corps of Engineers’ observers told the tug-barge skipper to evict the several hundred pound freeloader. And the skipper responded by saying “you do it,” Ellis said.
The sea lions have in recent years increased their presence in the waters below Bonneville Dam, feeding on salmon and steelhead spawners that are looking for an upstream passage route. The fish ladders allow fish passage but bar sea lions from passing over the dam there.
A sea lion or two have been seen in years past above the dam, sometimes enjoying a feast at the end of the fish ladders where salmon pour into the forebay. One of the animals how upstream is believed to have been above Bonneville since last year. The California sea lions typically dip into the river in late winter and spring, then leave at the end of May to swim down the Pacific Coast to their southerly breeding grounds.
This year the number of animals above the dam seems to be up, and the animals are wandering. They’ve been seen at The Dalles Dam, located 45 miles upstream, as well as the city of The Dalles marina boat docks, and at Cascade Locks and other locals. And since the beginning of the spring chinook salmon run in April, they’ve been taking advantage of salmon stalled in tribal gill-nets, dip and hoop nets, and stealing fish off the end of fishing lines.
“They have been raising quite a bit of hell in our tribal subsistence permit fishery,” Ellis told the Columbia River Compact Tuesday. While tribal fishing so far this season has been focused on satisfying subsistence needs, the bi-state Compact approved the sale of fish caught in tribal hoop nets, dip bag nets, and rod and reel with hook and line in Zone 6 upstream of Bonneville and in designated fishing areas along the Washington shore just below the dam. Allowable sales includes salmon, steelhead, shad, carp, catfish, walleye, bass and yellow perch.
Because of the sea lion looting, the tribes (Nez Perce, Umatilla, Warm Springs and Yakama), in an April 17 letter to Oregon Department of Fish and Wildlife Director Roy Elicker signed by CRITFC Executive Director Paul Lumley, asked for help.
“At least three sea lions are currently in the Bonneville pool and disrupting ceremonial fishing,” the letter said. “The fishers are suffering gear damage and catch loss from these sea lions. As you know a very small number of chinook salmon have crossed Bonneville Dam to date and catching these fish is difficult enough without interference from sea lions. We request that the State of Oregon place a sea lion trap in the Bonneville Dam forebay to remove these animals.”
At the time, a late-arriving salmon run was limiting the tribal opportunities to catch fish for ceremonial event.
“It’s been a real hardship for the fishermen,” according to CRITFC’s Doug Hatch.
ODFW, which is leading an effort to trap and remove sea lions preying on salmon below the dam, last week moved two of its four traps to above the first powerhouse – located on the Oregon side of the river. The trapping effort below the dam is ongoing, but recent high water conditions below the dam’s second powerhouse near the Washington shore precluded safe operations there, so the floating traps were moved upriver.
Now, the wait is on, according to Robin Brown, the ODFW’s Marine Mammal Project leader. Animals seen upriver in years past have spent time above powerhouse one feeding on salmon emerging from the fish ladder.
“We really haven’t seen that” thus far this year, Brown said. The hope is that the pinnipeds will land on the traps, so they can be given a ride downstream. Brown said that all three of the animals believed to be plying the Bonneville reservoir are unmarked. Researchers over the years have captured and branded or otherwise marked hundreds of sea lions so that they can be identified for researcher purposes.
One, however, has been identified via natural markings as an animal observed to have taken salmon below Bonneville Dam. That qualifies him for removal under the program being implemented by the states or Oregon and Washington. The removal program is intended to reduce predation on salmon and steelhead stocks that are listed under the Endangered Species Act.