Episode 1604: California Sea Otters: Life on the Edge

Adored by many for their cuddly appearance, southern sea otters are voracious predators that need to eat the equivalent of 25% of their body weight a day to survive. Once nearly hunted to extinction, these threatened marine weasels have made a slow comeback on California’s central coast, positively impacting the health of kelp forests, seagrass meadows and salt marshes in the process.

But for southern sea otters to continue to recover, the population needs to expand its current range, something that hasn’t happened in 20 years, and is unlikely to occur naturally given the increased shark attacks along its boundaries.

Dedicated scientists study and monitor the health of this keystone species, and now the U.S. Fish and Wildlife Service is in the early stages of considering sea otter re-introduction to Northern California and Oregon. Researchers say that re-introducing sea otters to parts of their former range will likely have many positive effects on ecosystems that humans depend on which are threatened by climate change. The challenge is making sure that potential impacts are fully investigated.

Experts

Meet the experts featured in this episode.

Episode Photos

1 / 28

Southern sea otters are adored by many along California's central coastline.

2 / 28

The fur trade nearly exterminated sea otters in the North Pacific. In California, just a small population of about 50 animals survived along Big Sur's rugged coast.

3 / 28

Sea otters have voracious appetites. Because of their high metabolism, the animals need to consume 25% of their bodyweight daily to stay alive.

4 / 28

Sea otters have the densest fur of any mammal. To stay warm in the cold waters of the North Pacific, the animals must spend 8-12% of their time grooming their fur to keep it in good condition. A well-groomed sea otter coat creates an insulating air layer that prevents the cold water from ever touching their skin.

5 / 28

The small town of Morro Bay on California's central coast is a great place to observe resting sea otters from the waterfront.

6 / 28

Given the sea otters’ fast metabolism and lack of energy stores, each disturbance that leads them to burn calories is detrimental to their long-term health and survival. Volunteers with Sea Otter Savvy regularly measure the level of human disturbance at different sites.

7 / 28

Sea Otter Savvy's research has shown that the average otter is disturbed six times a day by human activities, which can be detrimental to their longterm health and survival.

8 / 28

Sea otter moms are especially vulnerable to disturbance because they need to consume 30-40 percent of their bodyweight daily to feed themselves and their pup.

9 / 28

Sea Otter Savvy's Director and Senior Scientist Gena Bentall (right) works closely with businesses that are involved in marine recreation. Outfitters who promote respectful wildlife viewing are eligible for the Community Active Wildlife Stewards, or CAWS, certification.

10 / 28

Monterey Bay Aquarium Sea Otter Program Manager Jessica Fujii uses radio telemetry to locate a tagged sea otter. The aquarium runs a successful surrogacy program that pairs orphaned wild pups with adult females in their care. Once the orphans are old enough, the animals are returned to the wild.

11 / 28

Elkhorn Slough, an estuary about 30 miles north of Monterey, is currently home to the highest density of southern sea otters in California.

12 / 28

More than a hundred sea otters live in Elkhorn Slough.

13 / 28

This makes the slough a great place to study social behaviors and chronic stress in the animals.

14 / 28

Lilian Carswell is overseeing that study. In addition to being the Southern Sea Otter Recovery and Marine Conservation Coordinator for the U.S. Fish and Wildlife Service, she is also working on her Ph.D. at UC Santa Cruz.

15 / 28

A resting sea otter.

16 / 28

Sea Otter Research Ecologist Michelle Staedler is also part of the study. She observes the animals several days a week and collects data on their location, behaviors and who the animals are with.

17 / 28

The research team attached unique flipper tags to 90 otters so far, making it possible to identify and closely observe individual animals.

18 / 28

A combination of differently colored and numbered tags allows scientists to track individual otters.

19 / 28

Sea otters like to rest in groups known as "rafts."

20 / 28

As the number of sea otters in Elkhorn Slough has grown to more than a hundred, the furry marine weasels started utilizing the salt marsh to rest and forage as well.

21 / 28

Recent research has shown that sea otters have a positive impact on the health of seagrass. The marine mammals feed on crabs which in turn forage on herbivores that keep the seagrass clean of algae. By keeping the number of crabs in check, the seagrass can thrive.

22 / 28

Melissa Miller, D.V.M., Ph.D. is a Wildlife Veterinarian & Pathologist for the California Department of Fish and Wildlife Office of Spill Prevention and Response. She conducts postmortem examinations on sea otters that are found stranded along the coast.

23 / 28

Sea otters are susceptible to the impact of harmful algal blooms and a variety of land-based parasites that wash into the sea and accumulate in the otters' prey.

24 / 28

For southern sea otters to continue to recover, the population needs to expand its current range, something that hasn’t happened in 20 years, and is unlikely to occur naturally given the increased shark attacks along its boundaries. Experts are now evaluating the feasibility of re-introducing the marine mammals to parts of their former range.

25 / 28

Brent Hughes, Ph.D. has been studying a variety of habitats in Northern California to determine if they are suitable for the animals now.

26 / 28

Researchers are analyzing habitats for food availability and potential threats to sea otters, while also taking into consideration if the animals could help improve the health of an ecosystem.

27 / 28

Members of the Changing Seas team with researchers Michelle Staedler (second from left) and Lilian Carswell (right.)

28 / 28

Sea otters may appear cute and cuddly, but they are fierce predators that lead challenging lives.

Special Thanks:

Inn at Morro Bay

60 State Park Rd.

Morro Bay, CA 93442

805-772-5651

Whisper Charters

2370 HWY-1

Moss Landing, CA 95039

831-207-6305

Image Credits

Changing Seas would like to thank the following individuals and institutions who kindly allowed their footage, images and other media to be used in this production: