Fury erupts as thousands of sea lions face ‘mass slaughter’ in three US states

A debate has intensified in the Pacific Northwest as officials consider expanding the lethal removal of sea lions in an effort to protect dwindling salmon populations and bolster regional fisheries.

An estimated 4,000 to 4,500 sea lions live in the Columbia River basin in Washington, Oregon, and Idaho; The animals feed on migrating salmon and steelhead here.

Supporters of the effort argue that sea lion predation has become a growing threat to already vulnerable fish species that local communities, tribal fisheries and commercial fishermen rely on.

The move gained momentum in April after Washington Rep. Marie Gluesenkamp Perez called on the Trump administration to approve “direct, lethal removal” of sea lions to help protect threatened salmon populations.

Sea lions sometimes eat four times more salmon than fishermen and Native American tribes harvest in a year, Gluesenkamp Perez said.

He also noted that nearly one in four fish passing through Bonneville Dam during the spring 2025 season had injuries associated with sea lion bites.

But critics argue that sea lions are unfairly blamed for the crisis caused largely by habitat destruction, overfishing, hydroelectric dams and climate change.

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The Columbia River Basin once contained between 10 million and 16 million salmon and steelhead; but more than a third of these historic populations are now extinct; many remaining species are considered critically low.

Sea lions often congregate below the Bonneville Dam, where migrating fish are forced to pass through narrow passages, making them easy targets for predators.

Gluesenkamp Perez argued that the crisis had reached a breaking point, claiming that sea lions were sometimes eating four times more salmon than fishermen and Native American tribes harvested in a year.

He also said nearly one in four fish passing through Bonneville Dam during the spring 2025 season had injuries associated with sea lion bites.

‘It is an insult to my community to waste taxpayer money while grocery prices are at record highs and fishermen are denied the ability to put food on the table for their families,’ he said. The Daily Mail contacted Gluesenkamp Perez for comment.

Sea lions remain protected under the Marine Mammal Protection Act of 1972, which generally prohibits the harassment, capture or killing of marine mammals without federal authorization.

Congress expanded removal powers in 2018, allowing wildlife managers to remove up to 540 California sea lions and 176 Steller sea lions over five years, but officials say far fewer animals are actually removed.

Under current rules, authorities trap sea lions near dams and fish ladders before euthanizing them under veterinary supervision. Authorities also use underwater explosive deterrents known as ‘seal bombs’ to divert animals from salmon migration routes.

Authorities have used underwater fireworks to deter sea lions from the waters, but studies have found that the non-lethal tactic can cause serious injuries and even death. Pictured is a sea lion suspected of being exposed to fireworks and its eyes bulging

Seal bombs explode underwater, creating shock waves that can damage marine mammals’ hearing or cause serious injury. Autopsies performed on sea lions

The Marine Mammal Center found trauma believed to be related to the explosions, including jaw fractures, burns and severe tissue injuries.

NOAA Fisheries has previously identified sea lion predation as a significant threat to many endangered salmon species in the Columbia Basin. Officials also argued that nonlethal deterrence alone did not prevent sea lions from returning to important feeding grounds near the dam.

But critics argue that sea lions are just one factor contributing to the salmon crisis, and say habitat destruction, overfishing, hydroelectric dams and climate change play larger roles in the decline.

Supporters of the effort argue that sea lion predation has become a growing threat to already vulnerable fish species that local communities, tribal fisheries and commercial fishermen rely on

Hydroelectric dams have been blamed for disrupting migration routes, altering river habitats and increasing mortality rates for young salmon heading to the ocean and adult fish returning upriver to spawn.

Experts say urban development and water diversion are also reducing and warming river habitats necessary for salmon to spawn, while climate change is disrupting both the freshwater and ocean stages of the fish’s life cycle.

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Another shared: ‘I do not support the mass slaughter of non-invasive sea lions because they prey on their natural prey.’

But others have defended the removals, arguing that sea lions are increasingly learning to congregate near bottlenecks where salmon are particularly vulnerable.

One local user wrote: ‘They don’t naturally come this close upstream, but have learned that fish like to congregate near obstructions like Bonneville or Willamette Falls. ‘They are destroying native salmon and sturgeon populations.’