Southern sea otter floating in wild giant kelp beds © Kiliii Yuyan/Kiliii Fish Photography

Pushing the Boundaries of Sea Otter Recovery

How do wildlife management and sea otter ecology come together to support a healthy coast? After growing from a low of about 50 animals in the early 1900s to around 3,000 today, the population of southern sea otters has plateaued. To fully recover, otters must return to more of their historical range along the California coast. In a new study, our researchers identified some of the biggest obstacles.

The study, which analyzes data from 725 stranded otters over 30 years, reveals a critical relationship between healthy kelp canopy coverage, sea otter mortality and population recovery. It finds that loss of kelp raises the risk of white shark bites, especially at the two ends of sea otters' range along the Central Coast. These bites can be fatal to otters, and may prevent the population from fully recovering. The paper provides scientific insight to guide the next phase of our work: helping otters repopulate the broader California coastline their ancestors inhabited before the fur trade.

The past year brought other milestones. In 2018, we received special permission for a wild, rehabilitating otter to practice her deep-diving skills while on exhibit. This novel experience allowed us to more fully prepare the otter for her successful release.

Southern sea otters Kit, Gidget, Ivy, Rosa and Abby at the Monterey Bay Aquarium
Rosa, Ivy, Gidget, Kit (back row, left to right) and Abby (front) foster and serve as companions for stranded pups, teaching them skills they need to return to the wild. We mourned the loss of Gidget in February 2019, and acknowledge her contributions to the surrogacy program. A sample of Gidget's blood was used to sequence the sea otter genome for the first time. Her DNA will be a reference point for future genetic studies of southern sea otters.

We also collaborated with Google to share the story of California's sea otters with a global audience. "The Return of the Sea Otter," a web-based Google Voyager experience, takes users to the shores of Point Lobos, Moss Landing and Cannery Row to discover why sea otters are vital to the health and economy of California's coast.

And in a long-standing collaboration with the U.S. Geological Survey Alaska Science Center, our researchers are looking to northern sea otters for clues. By studying this thriving population, our researchers gain a deeper understanding of their more vulnerable California cousins.

Thumb through the photos in the Aquarium archives, and you'll find 1980s-era images of our staff in wetsuits, walking along the shores of Monterey Bay with fluffy sea otter pups tucked under their arms.

Southern sea otters had been brought to the brink of extinction, and the species' potential for recovery was uncertain. Until the Aquarium began caring for stranded pups in 1984, no one knew how to keep them alive once they became separated from their mothers. We created a formula for stranded, nursing pups and pioneered a successful protocol for sea otter rescue, rehabilitation and release.

Over the decades, our team has become integral to the recovery of California's threatened sea otters.

Today, our animal care specialists no longer don wetsuits to hand-rear otter pups. Instead, they wear body- and face-concealing uniforms to prevent otters from becoming comfortable with humans. Our resident female adult otters serve as foster moms to teach pups critical survival skills.

Aquarium staff member grooming a sea otter pup
Our animal care specialists conceal themselves to reduce the chance of otters becoming comfortable with humans.
Aquarium staff member releases a sea otter into the wild from a boat
Aquarium field response coordinator Karl Mayer releases a rehabilitated sea otter back into the wild.

Thirty-five years after our first rescues, our Sea Otter Program is laying the groundwork for the future. The diet and care protocols developed by our veterinarians and staff have given stranded sea otters a strong chance to survive once they're released back into the wild. Still, southern sea otters need our help to rebuild their population along the California coast.

Our researchers have contributed to landmark studies on sea otters as a keystone species, critical to the health of local estuaries and kelp forests. One study found that nearly 60 percent of the otters in Elkhorn Slough, an estuary just north of the Aquarium, are descendants of otters released from our surrogacy program. We're excited about the potential for sea otters to help restore ecosystems along more of the California coast.

Over the decades, our team has become integral to the recovery of California's threatened sea otters. Aquarium experts continue to advance scientific knowledge, influence state and federal management, and educate the public about sea otters' essential role in maintaining the health of coastal ecosystems.

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We study sea otters to help their population recover. Support our important work with this threatened species.

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Annual Review 2018 (PDF)

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