Wildlife managers in some parts of the US have been given permission to start killing hundreds of sea lions in a bid to protect salmon and steelhead trout.
The marine mammals have been feasting on the migrating fish in the Columbia River basin where they bottleneck at dams or where they head up tributaries to spawn.
Shaun Clements, senior policy analyst for the Oregon Department of Fish and Wildlife, said: “These are places where the fish are really vulnerable.
“We have to manage this so the fish can get through to spawn.”
The new permit allows the states of Washington, Oregon and Idaho and several Native American tribes to kill 540 California sea lions and 176 Steller sea lions, from Portland to the McNary Dam upriver, as well as in several tributaries.
It is the first time they have been allowed to kill the much larger Steller sea lions.
Wildlife officials have faced a long-running conundrum over pitting the mammals, whose populations are healthy, against protected fish runs.
Columbia River salmon are also a key food source for the Pacific Northwest’s endangered population of orcas, which scientists say are at risk of extinction if they can’t access more food.
Authorities have tried a number of other methods to deter the sea lions over the years, including traps, rubber bullets and explosives, with no success. The sea lions would return days after being relocated hundreds of miles away.
The Port of Astoria in Oregon even tried a fake, motorised orca made of fiberglass in a futile effort to keep them off its docks.
And around 13 years ago, authorities began killing some sea lions at the Bonneville Dam on the Columbia River under restrictions that required them to first document each targeted animal in the area five times, observe it eating salmon and wait for it to enter a trap. Some 238 have been killed there.
Now, wildlife officials will be able to tranquilise, capture or trap any sea lions in the area, before bringing them to another location to give them a lethal injection. The permit forbids them from shooting the mammals.
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Sharon Young, senior strategist for marine wildlife at the Humane Society, called the sea lions the least of the salmon’s problems.
She said that fishing, competition from hatchery fish and habitat loss, including dams and culverts that block their passage or raise water temperatures, are much more of a threat.
“Killing the sea lions isn’t going to address any of that,” she said.
“It is only going to distract from what they aren’t doing to address the real problems salmon are facing. You’re killing sea lions for nothing.”