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Southern Sea Otters

The southern sea otter is making a slow recovery, after being hunted to the brink of extinction in the 18th and 19th centuries.

The sea otter (Enhydra lutris) has a historic range that forms an arc across the North Pacific Ocean, stretching from the shores of Baja California up the west coast to Alaska and across the Bering Strait to the Kamchatka Peninsula and down to the islands of northern Japan. Southern sea otters (Enhydra lutris nereis), sometimes referred to as California sea otters, make up a subspecies of sea otter that ranges along the central California coast from San Mateo to Santa Barbara Counties. Southern sea otters were listed as a threatened species in 1977 under the Endangered Species Act and are protected under the Marine Mammal Protection Act.

Sea otters once numbered in the hundreds of thousands and were common throughout the North Pacific. For thousands of years, the native peoples of Kamchatka hunted them for both food and fur. With the advent of the Pacific Maritime Fur Trade, starting in the 1740s, the scale of hunting was greatly increased. Sea otter pelts were valued for their rich and luxuriant fur, which has nearly one million hairs per square inch, the thickest fur of any mammal. The trade was dominated by Russian, American, and British hunters, who brought sea otter furs to China, where the soft fur was highly prized for clothing, coats, and trim.


"Of all these furs the skins of the sea-otters are the richest and most valuable. ... they are called by the Russians Boobry Morfki, or sea beavers, on account of the resemblance of their fur to that of the common beaver."
    William Coxe, 19th century English historian

As demand for sea otter pelts increased, so did the prices and they became known as "soft gold" in the Chinese market. By 1903, one sea otter pelt commanded more than $1,000 in the London market. As a result, sea otter populations rapidly became depleted throughout their range. They were believed to be close to extinction in 1911, when Russia, Japan, Great Britain, and the United States signed the Treaty for the Preservation and Protection of Fur Seals, which imposed a moratorium on the harvesting of sea otters.

Since 1911, sea otter populations have slowly recovered, although they still face threats such as poachers, oil pollution, and orca predation. Recovery has been much stronger in Alaska and other northern locations than in California, where the southern sea otter population numbers approximately 2,900. Each year, researchers from the the U.S. Geological Survey, the California Department of Fish and Wildlife, Monterey Bay Aquarium, and the University of California Santa Cruz conduct a census of sea otters to aid in the recovery plan for the U.S. Fish and Wildlife Service.

The sea otter is considered a keystone species, one that has a disproportionately large effect on its environment relative to its abundance. Sea otters feed on sea urchins, playing a critical role in maintaing the health of kelp forest ecosystems. They also consume filter-feeding benthic invertebrates, resulting in the removal of contaminants and disease-causing pathogens from near-shore waters. Sea otters are highly effective sentinels of the health of our ocean, making their recovery an important goal of The Marine Mammal Center.

Southern Sea Otters at The Marine Mammal Center
The Marine Mammal Center has rescued more than 350 southern sea otters since its inception in 1975. They have been rescued for a variety of reasons, including malnourishment, disease, and maternal separation. Most of these rescued animals were transferred to the Monterey Bay Aquarium for care and rehabilitation. Among these patients were Calloway and Repo, whose cases represent an overview of the Center's work with this threatened species.

Calloway, a southern
sea otter pup

Calloway was rescued in 2003 when she was found separated from her mother before she had been weaned. After initial care and rehabilitation at the Center, Calloway was transferred to the Monterey Bay Aquarium. She was released back to the ocean shortly thereafter and according to Michelle Staedler from the Aquarium's Sea Otter Research and Conservation department, was thriving in the wild:

"Calloway has been out on her own now for just over two weeks and seems to be doing quite well. She has made the Monterey Dunes colony near and offshore areas her home. She is doing great at finding herself tasty large cancer crabs for her meals!! She varies from being 300 meters offshore to 1.2 KM offshore. So - at this point since she has successfully passed the two week mark - she is well on her way in the otter world!"

You can adopt Calloway today and help other patients at The Marine Mammal Center.

Repo, a southern
sea otter pup

Repo was rescued by the Center when he was orphaned at just six weeks of age. He was found on a beach in Morro Bay, San Luis Obispo County. Repo was so young when he arrived at the Center that he needed 24-hour care. Volunteers bottle fed him every three hours, monitored his swims, and helped him groom his thick, insulating fur.

After six weeks at the Center, Repo was transferred to the Monterey Bay Aquarium to finish his rehabilitation with a surrogate sea otter mother. Once healthy, he was fitted with a radio transmitter and released back into the wild.

You can adopt Repo today and help other patients at The Marine Mammal Center.

Watch a heartwarming video of a sea otter pup that was successfully reunited with her mom in Morro Bay. This was a cooperative effort between The Marine Mammal Center and the California Department of Fish and Wildlife. 


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Teach your kids about wildlife with this adorable Sea Otter Puppet. Makes a great learning toy for ages 3 and up.

When you Adopt Repo the Sea Otter, he comes with an adoption certificate, a photo, and a plush toy.

Stay warm in a pair of Sea Otter Socks. Featuring prints of reclining otters, they come in sizes for kids and adults.


Learn more about Sea Otters.

Help The Marine Mammal Center when you Adopt Repo or Calloway.

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