Name: California Sea Otters: Life on the Edge | Changing Seas
Uploaded: 2025-06-29T05:40:54.000Z
Duration: 26 min 43 s
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Their antics are adored by many along California's central coast.

They are cute, they are furry, they look like you just want to give them a hug.

They are remarkable predators in the ocean.

There's actually over 60 different species of prey items that otters eat.

Things like crabs, worms, clams, marine snails.

Obviously they're really famous for being big consumers of sea urchins.

They have an extremely high metabolic rate.

They eat 25% of their biomass every day, just to stay alive.

It's about 20-25 pounds of food that they need to eat.

They don't have a blubber to help keep them warm, and so they have to rely on their fur and their high metabolism.

Sea otters have the densest fur of any mammal.

They have approximately a million hairs per square inch.

And it was this really dense fur that really attracted the fur trade, and that was part of their demise.

It was referred to as soft gold because it was so valuable.

The global sea otter range used to be throughout the entire North Pacific from Japan to halfway down Mexico.

And that was probably 200-300,000 animals.

But the booming fur trade in the 1700s and 1800s nearly exterminated sea otters in the North Pacific until the furry marine weasels received protection from hunting under the International Fur Seal Treaty in 1911.

After the fur trade, sea otters were reduced to just a few remnant populations.

And so the southern sea otter was reduced to just a single little population off the coast of Big Sur in central California.

It's estimated that only about 50 animals survived along Big Sur's rugged coastline.

Since then, all of the populations have recovered to some extent, but the southern sea otter here in California has been the slowest to recover and has recovered the most limited percentage of its historic range.

Despite the many challenges sea otters face, as keystone predators, they play a vital role in the ecosystems they inhabit.

And these are ecosystems that many other animals and humans depend on.

How do sea otters impact the environments they live in?

And what is keeping them from expanding their range in California?

NASA Jet Propulsion Laboratory  Major funding for this program was provided by The Batchelor Foundation, encouraging people to preserve and protect America's underwater resources.

Additional funding was provided by Trish and Dan Bell and by the Perot Family Endowment for Environmental Education.

In the quaint town of Morro Bay on California's central coast, He's so cute!

curious onlookers delight in catching a glimpse of the southern sea otters that rest along the waterfront.

They want to get in and get the photo, and at that point when the animal's resting is when they're most vulnerable to the impact of someone just getting too close.

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.

This is especially true for sea otter moms who need to consume 30 to 40 percent of their body weight daily to feed themselves and their pup.

And they can be really extra vulnerable at that time, and that's when people love them the most, right?

So just asking folks not to love them to death.

They'll look at you, and that's a warning sign, so we're always telling people be alert for that, and then stop if you see it and back away.

To get the word out, Jenna works closely with businesses that are involved in marine recreation.

I just wanted to bring you your flag!  Outfitters who promote respectful wildlife viewing are eligible for the Community Active Wildlife Stewards, or CAUSE, certification.

CAUSE has given us great verbiage and ways to approach people so that we can really get the point across to them without offending anyone, so to speak.

In addition to outreach, Sea Otter Savvy is also conducting research.

Volunteers regularly measure the level of sea otter disturbance at different sites.

They do a two-hour session where they scan from one side to the other every 15 minutes.

During those scans, the team records the sea otter's activity and their distance to human stimuli, such as onlookers, boaters, or kayakers.

We've collected data at nine different sites all along the Central Coast, and so we have this huge data set over ten years recording all kinds of elements of sea otter disturbance by human activities, and the average across all of our sites is six disturbances per day.

So it's not that one disturbance, it's the one after and the one after that and the one after that, and that adds up to a cumulative impact for these animals.

A few hours north along the coast, visitors to the Monterey Bay Aquarium have a chance to see and learn about rescued sea otters up close.

As sea otters stranded and needed help, we were learning how best we could give them the care and get them back out to the wild.

In the early 2000s, we started this new program that we call our surrogacy program, where we would take care of the sea otters where we pair these orphaned pups with our female adult sea otters that live here at the aquarium.

When an orphaned pup arrives at the aquarium, the staff takes great care to keep the animal as wild as possible.

We provide hands-on care while wearing disguises so that the pup doesn't associate people as a mother.

We're having to bottle feed the pup, groom its fur.

Once a pup is about two months old and can eat solid foods, the team introduces it to a surrogate mom.

We've had really good success with them being super ready to start sharing food, grooming the pup, all those great behaviors.

And we'll watch as they form this maternal care bond and continue to care for them until the pup is about six months old.

That's about the age that they wean or separate from their mom in the wild, and so after that, they're practicing all those essential skills that they learned and getting ready to go back out into the wild.

When a pup is ready to be released, the aquarium's veterinary team gives the animal a thorough health exam.

And they will do a surgery to implant the radio transmitter, and that transmitter lasts for three to four years, and that really helps us find the animal once they're back out in the wild.

Each otter has their own unique frequency, and we can go along the shoreline and listen to all those different frequencies, and if they're in the area, we'll get a beeping signal, and that helps us know what direction they're in, and then we can start looking with really high-powered telescopes to actually try and find that otter and see what they're doing and how they're doing.

And we'll follow them every day for two weeks to really make sure they're able to find food, that they're not getting too stressed, and then after that, they're considered officially released in a wild otter again.

And we'll continue to follow them to see how they're surviving, how they're reproducing, and where they're moving to in the range.

Early on, the aquarium staff noticed that many of the released otters moved to Elkhorn Slough, an estuary about 30 minutes north of the aquarium.

And so we just started going there directly, and it was a very low population of sea otters at that time.     There were maybe 20 were living in the estuary, and so for over 15 years, we focused our release of those surrogate reared otters into the estuary, and about 37 of them were released over that time, and we also saw the population grow to over 100.

Right now, Elkhorn Slough is the highest density of sea otters in one particular place.

This makes the slough a great place to study social behavior and chronic stress in sea otters.

And what I would really like to know is how important social bonds are to sea otters.

First of all, whether those bonds even exist, who's affiliated with who, how long those affiliations last, and whether there's any genetic basis to it.

In addition to being the Southern Sea Otter Recovery and Marine Conservation Coordinator for the U.S.

Fish and Wildlife Service, Lillian Carswell is working on a Ph.D. at UC Santa Cruz.

We know that sea otters have lots of stressors in their environment.

There's food limitation, there's disease, there's human activity, there's predators.

How can they rely on each other and perhaps have improved fitness because of these relationships?

To gain insight into sea otter relationships, Lillian, together with her collaborators, attached unique flipper tags to 90 otters so far, making it possible to identify and closely observe individual animals.

We have people going out several days during the week, and we're getting the GPS location of the animal, getting its behavior, whether it has a pup, and especially who it's with.

And sea otters tend to do most activities on a solitary basis, but when they rest, they like to be together.

And so is there a regular group of otters, or are they moving around between these different groups?

And so our initial results indicate that there really are Lillian is also analyzing hair and whisker samples to evaluate cortisol levels as a measure of chronic stress.

Sea otters in Elkhorn Slough appear habituated to human disturbances from kayaks and boats that keep a proper distance.

But are those habituated sea otters actually experiencing elevated levels of chronic stress is something I would like to understand.

As the number of sea otters has grown to more than 100, the slough itself has changed as well.

Seagrass is healthy and has spread, despite receiving lots of nutrients from agricultural runoff that usually causes algal blooms.

The algal blooms in theory should be totally smothering the seagrass.

And in fact, it was in the early 80s, it was almost totally gone from the ecosystem.

So what changed that suddenly allowed seagrass to thrive?

The seagrass are home to these really important invertebrates.

They're herbivores that eat the algae that grows on the seagrass.

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California Sea Otters: Life on the Edge | Changing Seas

vulnerable

chronic

potential

metabolism