SalmonScape is an interactive mapping application designed to display and report a wide range of data related to salmon distribution, status, and habitats. The data sources used by Salmonscape include stream specific fish and habitat data, and information about stock status and recovery evaluations
California sea lion below Bonneville Dam
Sea Lion predation in 2016:
Annual report by U.S. Army Corps of Engineers of sea lion predation and efforts to protect salmon and steelhead below Bonneville Dam. Learn More >>

Restoring balance between predators and salmon

Columbia River salmon and steelhead face a serious threat from California sea lions that prey on fish waiting to move up the fish ladders at Bonneville Dam in early spring. Each year since 2002, sea lions have consumed tens of thousands of migrating fish, many from threatened and endangered runs protected under the federal Endangered Species Act.

The federal Marine Mammal Protection Act recognizes that predation by a growing sea lion population can jeopardize salmon and steelhead stocks at risk of extinction. For over a decade, wildlife managers from Washington and Oregon have worked with federal and tribal partners to chase sea lions away from the area immediately below Bonneville Dam. But those efforts, alone, have not proven effective in curbing salmon predation by a robust population of California sea lions.

In March 2008, fish and wildlife agencies in Washington, Oregon and Idaho received federal authorization to remove California sea lions that have been observed preying on salmon and steelhead below Bonneville Dam. The authorization, renewed in 2016 for five years, allows wildlife managers to use lethal measures to remove sea lions that meet specific criteria Whenever possible, the states have worked to relocate these animals to zoos and aquariums.

Through 2016, wildlife managers removed a total of 161 California sea lions – 15 of which were sent to zoos and aquaria – that met the federal criteria. These efforts have helped to control the portion of the salmon and steelhead runs taken by sea lions below Bonneville Dam, although thousands of fish are still lost to predation every year.

In 2017, the Washington Department of Fish and Wildlife and partnering agencies will mark their 13th straight year in the ongoing effort to manage sea lions preying on protected Columbia River salmon runs.