Addressing the Columbia River Sea Lion Issue

Sea lion presence in the Columbia River is not new; tribal oral histories describe the occasional sea lion venturing as far upriver as Celilo Falls, but as a rare and noteworthy event, not a sign of them present in any numbers or on any regular basis. That pattern held for generations: sea lions were only rarely seen even at Bonneville Dam, closer to the river’s mouth, from its construction in 1937 until 2000.

That changed in the early 2000s, driven by three converging forces: California and Steller sea lion populations recovered to the point of approaching carrying capacity pushing more male animals further from rookeries; changing ecosystem conditions; and learned foraging behavior, passed between individual sea lions, drawing them back to the Columbia each year.

Over the following years, sea lion predation grew, affecting tribal and non-tribal fisheries, hatchery broodstock needs, and spawning escapement for wild populations, including numerous ESA-listed stocks on the brink of extinction. The impact has been severe: sea lions eat an estimated 20 to 25 percent of the spring chinook run and reached nearly 50 percent in the worst year, with salmon making up nearly 100 percent of a sea lion’s diet once it moves upriver above the estuary. For comparison, salmon and steelhead make up only 10 to 30 percent of a sea lion’s diet in coastal waters and the estuary.

At Bonneville Dam, individual sea lions typically eat 3 to 5 salmon a day, and is the most significant cause of adult upriver spring chinook mortality over the past two decades — a toll that falls heavily on ESA-listed populations. In 2015, the worst year on record, sea lions took an estimated 224,450 salmon between the river mouth and Bonneville Dam, nearly matching the number of spring chinook that managed to pass the dam that year. This was four times the number of fish harvested by all Columbia River fisheries (tribal and non-tribal combined) that year.

Addressing the Situation

Co-managers agreed that the primary option to deal with the situation was through removal of the habituated animals, not only to spare salmon directly, but also to interrupt the spread of the behavior to more sea lions. This course of action, however, was limited by the Marine Mammal Protection Act.

Under MMPA protection, California and Steller sea lion populations rebounded to the point that they began impacting fisheries, particularly at pinch points like narrows and fish ladders. Prompted by sea lions threatening winter steelhead at Ballard Locks in Washington State, Congress amended the MMPA in 1994 (§120), allowing removal of individual sea lions shown to have a significant negative impact on ESA-listed salmon and steelhead, but requiring each animal to be individually identified through trapping, marking, and observation which was a slow, resource-intensive process.

These stringent guidelines were followed when the same situation developed in the Columbia River in 2001 (see images in next column), however they turned out to be difficult and ineffective in the much larger river system compared to the confines around Ballard Locks.

In 2018, another amendment was passed (§120(f)) that recognized tribal pinniped co-management authority for the first time and allowed area-based removal, rather than requiring case-by-case identification, within a confined stretch of the Columbia River.

Successes

Using these authorities, co-managers have had some significant successes. In 2018, before §120(f) became law, 22 percent of the Willamette River winter steelhead run was eaten by sea lions at Willamette Falls. This fell to under 2 percent in 2019 after a targeted removal program began. That shift moved the run’s extirpation probability from 99 percent down to 3 percent.

Across the broader removal program, 517 sea lions (398 California, 116 Steller) have been removed to date, with very conservative estimates crediting the program with saving roughly 100,000 adult Columbia River salmonids between 2008 and 2023.

Operating under the guidelines and authorities provided under §120(f), co-managers gained invaluable experience and scientific data in determining what works as well as revealed limitations hindering the effort. For example, most male pinniped haul-out sites are located in the Columbia River mainstem, but §120(f) restricts lethal removal to designated tributaries, preventing co-managers’ ability to act where sea lions concentrate.

Fine-tuning the Solution

To remedy these limitations, Rep. Michael Baumgartner (R-WA-5) and Rep. Emily Randall (D-WA-6) introduced H.R. 9621, the Northwest Endangered Salmon Predation Prevention Act, in July 2026. This bipartisan legislation, built on nearly 20 years of co-manager experience, amends §120(f) by expanding tribal, state, and federal co-managers’ authority to match the scale of the problem, giving them flexibility to adapt as conditions change, and encouraging development of new non-lethal deterrent technology.

1. Expand the Removal Area — Extends trapping and lethal removal authority to the entire Columbia River, rather than only the currently designated haul-out sites, reflecting the documented shift in pinniped range and behavior.
2. Adaptive Management Authority — Grants state and tribal co-managers flexibility to employ adaptive, science-based management strategies as conditions continue to change, rather than operating under a fixed set of removal rules.
3. Technology Accelerator — Establishes an accelerator to develop technologies that exclude seals and sea lions from salmon-bearing waters on the Columbia and elsewhere, adding a non-lethal tool to the co-managers’ options, as well as preventing future habituated males.

H.R. 9621 does not create a new management approach — it extends the existing methodology that has already been shown to work, to the geographic scope this problem actually requires. It is built on the same science-based, co-manager-led framework established under §120(f) in 2018 and is intended to protect Pacific Northwest salmon and steelhead runs, and the substantial public investment in dam passage, habitat restoration, and hatchery programs before further predation losses put those investments — and the tribal cultures, treaty rights, and regional fisheries at further risk.