NOAA 99-R107
Contact: Brian Gorman, Mike Fergus

NOAA Fisheries Responds to Congressional Request for Report

Rapidly growing populations of California sea lions and Pacific harbor seals on the West Coast can harm salmon stocks and other fish that are at low levels, including those listed or proposed to be listed under the federal Endangered Species Act, NOAA's National Marine Fisheries Service said in a report sent to Congress today. The report, also citing increasing incidents of sea lions that cannot be deterred from docks and marinas, said sea lions and harbor seals may be a threat to public safety at such locations.

Harbor seals, California sea lions and other marine mammals, such as whales and porpoises, have been protected by the federal Marine Mammal Protection Act since 1972. The results, according to the report, have been mixed. Some animals, like North Atlantic right whales, Steller sea lions and Hawaiian monk seals, remain critically endangered. Others, like California sea lions and Pacific harbor seals, have increased so rapidly that there are now frequent and serious conflicts between them and humans coast wide.

The fisheries service report, compiled with the assistance and concurrence of the Pacific States Marine Fisheries Commission and the fish and wildlife agencies of California, Washington and Oregon, was requested by Congress in 1994 to address the effects of rising West Coast pinniped populations on declining salmon stocks and interactions with humans. Congress would have to change the Marine Mammal Protection Act to put the report's recommendations into effect.

The 18-page report to Congress is based on a larger scientific report, also produced by the fisheries service, that describes robust and increasing seal and sealion populations on the West Coast. According to the latest figures available, the
scientific report estimates that by the mid-1990s there were 188,000 California sea lions and 76,000 harbor seals off California, Oregon and Washington. These populations have grown at an annual rate of about 5 to 7 percent, tripling their numbers since the 1970s.

Although not the primary cause for the salmon's decline, both seals and sea lions are known to eat fish from depressed stocks of salmon and steelhead, especially at areas of restricted passage like river mouths and dams, and this can prevent or delay recovery of declining fish populations. Fisheries service biologists note that there is a wide variety of other factors, including habitat degradation, dams, fishing and competition from hatchery salmon, responsible for these population declines.

"It's impossible to measure exactly how great an impact seal and sea lion predation is having on salmon," said William Stelle, NOAA Fisheries Northwest Region administrator. "But we do know that sound principles of wildlife management tell us that we should minimize the pressure being put on already badly diminished runs of these fish." Stelle said the report recommends applying a conservative principle in natural resource management, favoring the resource most in need of protection when information is uncertain.

The report says in certain situations where seals or sea lions are preying on salmonids listed or about to be listed under the Endangered Species Act, state and federal wildlife managers, under strict federal guidelines and as a last resort, should be permitted to lethally remove these marine mammals.

The agency's experience at Seattle's Ballard Locks, where for years sea lions preyed on an imperiled run of steelhead, shows that much of the predation is caused by a very small number of problem animals. Permanently removing only those animals, as was done with three Seattle sea lions in 1996, can virtually eliminate further predation.

"Human safety must be the prime concern when seals and sea lions directly encounter people," said William Hogarth, NOAA Fisheries Southwest Region administrator. "Our goal is to reduce interactions using every non-lethal technique available, but there are situations where a few animals are threatening people and property and we need more effective tools to deal with that conflict."

The report recommends that, in cases where seals or sea lions are causing repeated, serious conflict with human activity at locations such as fishing grounds or marinas, state or federal managers should be authorized to lethally remove identified problem marine mammals, if individual animals fail to respond to repeated attempts to deter them.

Other recommendations include developing safe and effective deterrents, so that lethal removal of problem animals is a seldom-used option. There is a "pressing need," according to the report, for research on the development of effective devices and methods that would drive away seals and sea lions from problem areas without harming them.

The report also recommends Congress consider reinstating the authority, removed from the federal marine mammal protection law in 1994, that allows a fisher to lethally remove a seal or sea lion to protect his catch or gear if the animal cannot be otherwise deterred. Such authority, the report says, would be only for certain fishers at specific sites and seasons, and only until effective non-lethal means to deter seals and sea lions can be developed.

The fisheries service is charged with protecting marine mammals under the Marine Mammal Protection Act and with recovering threatened and endangered salmon and steelhead under the Endangered Species Act.

Copies of the Congressional report, the 84-page scientific document that supports it, and other supporting materials are available on the Northwest Region office's home page at