Are Sea Otters Endangered? Status, Threats and Recovery

Yes. The sea otter is listed as Endangered on the IUCN Red List, and in the U.S. both southern sea otters and the southwest Alaska population of northern sea otters are listed as threatened under the Endangered Species Act. Every U.S. sea otter is also protected by the Marine Mammal Protection Act and managed by the U.S. Fish and Wildlife Service. Here is how they got here, what they face now, and the genuinely hopeful parts of the story.

Are sea otters endangered or threatened?

Both, depending on which list you check. On the global IUCN Red List, the sea otter (Enhydra lutris) is listed as Endangered, according to the IUCN Otter Specialist Group and Monterey Bay Aquarium. Under the U.S. Endangered Species Act, two populations carry the threatened label, the step below endangered.

In the U.S., sea otters are managed by the U.S. Fish and Wildlife Service (USFWS), not NOAA Fisheries. USFWS also notes that it is currently reviewing the southern sea otter's status under the ESA, so check its species page for the latest.

How did sea otters almost go extinct?

Their gorgeous fur nearly cost them everything. The Marine Mammal Commission estimates that 150,000 to 300,000 sea otters lived across the North Pacific before commercial hunting began in the mid-1700s. Almost two centuries of fur hunting followed, and the species came to the brink of extinction.

Estimates of how many survived vary: USFWS describes the worldwide population falling to just a few hundred animals by 1911, while the Marine Mammal Commission says only a few thousand remained. Either way, it was a sliver of what once was.

The turning point came in 1911, when the United States, Japan, Great Britain (for Canada) and Russia signed a treaty protecting North Pacific fur seals and sea otters from commercial hunting. At that time, USFWS says, only 13 small remnant populations were known, six of them in southwest Alaska. Otters from 11 of those groups went on to recover and recolonize parts of their old range.

In California, Monterey Bay Aquarium notes that about 50 sea otters were found off Big Sur in 1938, a tiny group in a state where otters had once ranged the whole coast.

Why are southern sea otters threatened?

Southern sea otters were protected under the Marine Mammal Protection Act in 1972 and listed as threatened under the ESA in 1977, according to Monterey Bay Aquarium. Today they live along a stretch of the California coast from about Half Moon Bay to near Point Conception, a small slice of a historic range that once ran from Baja California to Russia and Japan.

USFWS says southern sea otters have reclaimed only about 13% of their historical range, and that there has been no net range expansion in more than 20 years. A small group also lives at San Nicolas Island, the result of a translocation in the 1980s.

Two things worry experts most. Shark bites are a major cause of death, especially at the edges of the range, which keeps the population from spreading. And because the population is small and concentrated, Monterey Bay Aquarium warns that a single large oil spill could threaten the whole group.

What happened to sea otters in southwest Alaska?

A big, puzzling decline. In its 2005 listing announcement, USFWS said the Aleutian Islands held roughly 55,000 to 74,000 sea otters in the mid-1980s, nearly half the world's estimated population at the time. By the listing, the estimate there had dropped below 9,000, and the population segment as a whole had declined 56 to 68% over the previous 10 to 15 years.

The cause was not clear, but USFWS pointed to possible killer whale predation in the Aleutians, and the Marine Mammal Commission still lists it as a primary concern in the western Aleutians. Critical habitat was designated in 2009, and a recovery plan was finalized in 2013.

The Marine Mammal Commission reports a southwest Alaska stock estimate of 51,935 otters from a 2023 stock assessment, still more than 50% below mid-1980s levels. Farther south there is brighter news: the commission reports 1,343 sea otters counted in Washington in a 2023 survey.

What are the biggest threats to sea otters today?

No single villain, but a long list of pressures, documented by USFWS, Monterey Bay Aquarium, the Marine Mammal Commission and the IUCN Otter Specialist Group:

• Shark bites, a major cause of death in California, especially at the range edges.
• Oil, which coats the fur and destroys its insulation in an animal with no blubber.
• Disease outbreaks and contaminants, both listed by the Marine Mammal Commission.
• Water-borne toxins, which the Otter Specialist Group says are increasing as water warms.
• Ocean acidification, which USFWS says can be devastating to the shelled animals otters eat.
• Fishing gear and fishery conflicts, including entanglement and competition with shellfish fisheries.
• Killer whale predation in the western Aleutians.
• People: USFWS lists human disturbance and feeding as harms.

Are sea otters recovering?

In many places, yes, slowly and with setbacks. The remnant groups that survived the fur trade seeded recoveries across parts of the North Pacific. The Marine Mammal Commission says the population hurt by the Exxon Valdez spill was judged recovered to pre-spill abundance in 2013, 24 years after the spill. That is a long wait, but it is a comeback.

Rescue and rehabilitation help too. Monterey Bay Aquarium's sea otter program pairs stranded pups with surrogate mothers that teach them otter life skills before release, and the Vancouver Aquarium Marine Mammal Rescue Society cares for rescued marine mammals in British Columbia. Our guide to how orphaned pups are rescued and raised tells that story in detail.

How can you help sea otters?

Good news: most of the helpful stuff is simple.

1. Give wild otters space. Sea Otter Savvy recommends that kayakers and paddleboarders stay at least 5 kayak or board lengths away, and that boats never come within 100 feet. If an otter changes what it is doing because of you, you are too close. Keep dogs away from otters entirely.
2. Never feed or touch one. Under the Marine Mammal Protection Act, harassing or feeding a marine mammal counts as take, according to NOAA.
3. Report strandings instead of rescuing. USFWS says not to approach or pick up a sea otter in trouble. In Alaska, its stranding FAQ lists the Alaska SeaLife Center at (888) 774-7325 and the USFWS Marine Mammals Management Office at (907) 786-3800. In California, see the state's sea otter stranding response page for who to call.
4. Support rescue and research. A symbolic adoption is a fun way to chip in. See how to adopt a sea otter or the Adopt an Otter block on our homepage.
5. Keep watching and sharing. People protect what they love, and the cams make it very easy to love otters.

seaotter.cam is an independent fan site and is not affiliated with any aquarium, zoo, agency or organization mentioned here. Facts are drawn from the sources above; check them for the latest information.