Sea Lions vs Salmon?

The Marine Mammal Protection Act (MMPA) and Endangered Species Act (ESA) were implemented to help protect animal populations from extinction. However, the natural food web creates complex interactions where protected marine mammals like California and Steller sea lions are eating protected salmon species off the west coast of the United States (Yuskavitch 2016). Incidental take permits that allow the killing of sea lion have been issued to help reduce the loss of endangered salmon from predation since sea lions are near their optimum sustainable population (OSP) and less at risk of extinction (Congressional Research Service 2018). The conflict between protecting sea lions under the MMPA and salmon under the ESA is a false dichotomy that benefits neither species.

While sea lion predation of Columbia River salmon has been increasing from less than 1% to slightly over 5% in the past 20 years, those values are still negligible when compared to the loss from human activities (Congressional Research Service 2018, 1). Only wild salmon are protected by the ESA, so the actual predation is only a fraction of that amount and is an order of magnitude smaller than the 22% mortality rate from the Columbia River dam system alone (Yuskavitch 2016). The sea lion populations that are now at OSP should be seen as a win for the MMPA, however, Americans would rather point the finger at native species than their own actions for the loss of salmon.

For thousands of years, Indigenous Americans fished sustainably in balance with other salmon predators like sea lions. However, once colonists descended on the area and dammed the river system and fished at unprecedented levels, the salmon population began to nosedive. In 1883 alone, over 30 million pounds of salmon were shipped out from canneries on the lower Columbia River (Northwest Power and Conservation Council n.d). These unsustainable amounts continued for decades until salmon species were placed on the ESA list. Agency scientists have also found that removal of predatory sea lion and birds would provide little to no benefit to the salmon populations, yet incidental take permits have continued to be issued (Yuskavitch 2016).

Overall, the issue is not how to resolve the protection conflicts between the MMPA and the ESA, but how to reduce and remediate Americans’ impacts on the ecosystem. It will require a hard look at the value of dams, habitat destruction, and pollution more so then whether to remove a few hundred predatory sea lions or birds each year. To begin that process, we need to move past the concept of MMPA versus the ESA and focus on our human contributions to endangerment of species.


Congressional Research Service. 2018. “Sea Lion Predation on Columbia River Salmon and Steelhead.” Federation of American Scientists. Accessed July 22, 2022.

Northwest Power and Conservation Council. n.d. “Canneries.” Accessed July 23, 2022.

Salzman, James, and Barton H. Jr. Thompson. 2019. Environmental Law and Policy. 5th ed. St. Paul, MN: Foundation Press.

Yuskavitch, Jim. 2016. “Killing to Conserve.” Earth Island Journal. Spring 2016. Accessed July 22, 2022.

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