- In Alaska, a state brimming with iconic wildlife — from grizzly bears to king salmon, humpback whales to harbor seals — the charismatic, densely coated sea otter stands out as perhaps the state’s most hotly debated, controversial species.
- Sea otters were nearly hunted into extinction a century ago for their luxurious pelts. But they have been surging in population in the Gulf of Alaska, bringing both benefits to nearshore ecosystems and drawbacks to the shellfish economy (due to the otters’ voracious caloric needs).
- Described by commercial shellfish harvesters and Native Alaskans as pillagers of clams and crabs, sea otters are seen by many marine biologists as having positive impacts on kelp forests — important for biodiversity and carbon storage. Scientists stress that shellfish declines are complex, with sea otters being just one among multiple causes.
- Native Alaskans are the only people given free rein to hunt sea otters. But long-standing federal regulations stipulating who qualifies as Native Alaskan make it illegal for most to manage their own waters. Tribes are fighting for regulatory changes that would enable them to hunt and help balance booming sea otter populations.
HOMER, Alaska — Roarke Brown, a charter boat captain since 1972 in this picturesque fishing village, remembers being able to tread out onto the Kachemak Bay mud flats at low tide to fill a 5-gallon bucket with clams in little time with minimal effort. Tanner and Dungeness crabs? Drop a pot; haul it up crawling with crustaceans.
“There was a big commercial crab fishery here that’s been closed for decades,” Brown tells Mongabay, seated aboard the Pacific Shadow, his charter boat, in Homer’s busy harbor. “It’s just like a plowed field where we used to get clams. It’s no better for razors [clams) and mussels.”
There’s a complex tangle of historical, ecological and climactic explanations for the decline of nearshore shellfish populations off Homer, across the Kenai Peninsula, and throughout the expansive Gulf of Alaska. But Brown and his shellfishing brethren, in concert with some marine biologists and Native Alaskans, point to one culprit:
The incessantly hungry, steadily propagating northern sea otter (Enhydra lutris kenyoni).
Amid Alaska’s vast wilderness and rich coastal biodiversity — ranging from halibut to king salmon, bald eagles to tufted puffins, humpback whales to harbor seals — there is no more controversial species than the big-eyed, long-whiskered, luxuriously coated sea otter.

Across the gigantic arc of the Gulf of Alaska, from Glacier Bay in the state’s southeast, to Cook Inlet in the west, the rebounding population of sea otters represents a significant marine success story. Hunted nearly to extinction by Russian furriers in the early 1900s, otters gained protection in 1911 under the Fur Seal Treaty signed by the U.S., Great Britain, Russia and Japan.
In 1960, the state of Alaska gained management authority over sea otters and began reintroducing them to the Gulf. With the passage of the Marine Mammal Protection Act in 1972, the U.S. Fish and Wildlife Service took over management of spreading and growing sea otter populations.
Aided by abundant food sources and no real predators (aside from the occasional killer whale), sea otters mounted a steady comeback over recent decades, helping balance nearshore ecosystems made up of critical kelp forests, but also taking a multimillion-dollar bite out of the shellfishing economy.
The Alaska Department of Fish and Game estimates the state’s current sea otter population at around 70,000 — mostly concentrated in the south-central waters around Cook Inlet and Prince William Sound, as well as the southeastern waters closer to the state capital of Juneau, with fewer to the southwest along the Aleutian Islands.
While otters once inhabited the entire west coast of North America as far south as Mexico, some 90% of today’s population is in Alaska alone, with far fewer along coastal California and Washington states.
Sea otters offer an entertaining sight for tourists amid otherwise empty expanses of water. In Cook Inlet off Homer, water taxis and charter boats routinely glide past rafts of otters, bobbing and floating on their backs, often clutching pups, in tight clusters numbering into the hundreds. Try to get too close and they make eye contact, then quickly disperse and dive.

A voracious appetite
“Don’t get me wrong, I don’t hate otters,” Roarke Brown says. “When we take people out, everybody wants to see them. They’re cute and easy to find. But the marine [shellfish] trades are being hurt. Twenty years ago, there were only a few hundred [otters]. Now we have thousands.”
Only Native Alaskans can legally hunt these animals for their pelts — the densest fur of any mammal — having the potential to somewhat curb populations. But that activity, too, is legally fraught and controversial as the U.S. federal government keeps strict, some say racist, limits on who qualifies as a Native Alaskan.
In Mongabay’s two weeks of reporting in south-central Alaska, it became clear that the sea otter resurgence, and shellfish decline, embodies a nuanced story. It includes marine life adaptations to a massive natural disaster (1964’s earthquake that recontoured the Alaskan coastline to the sea otters’ eventual benefit), and a massive human-caused disaster (1989’s Exxon Valdez oil spill that wiped out all manner of marine animals, including otters).
Today, these furry marine mammals endure, with their story now expanding to include climate change impacts, the necessity for marine research, and the ongoing debate over how to manage an apex predator so lean and calorically needy that it must eat up to 30% of its body weight every day.
Otters continue to do so on a champagne diet of shellfish highly valued as delicacies by U.S. and foreign consumers, and as basic sustenance in roadless coastal Native Alaskan villages.

The science behind a species resurgence
Marine ecologist Heather Coletti, with the National Park Service in Anchorage, has been studying sea otters in Prince William Sound and beyond for a quarter-century. She’s been steadily building on the research of the late Jim Estes, a marine ecologist who made a key observation in the early 1970s while doing field surveys off the Aleutian Islands.
“When Jim went diving and saw where there were no sea otters, there was no kelp; it was like a monoculture of sea urchins,” Coletti tells Mongabay while sitting in a downtown park near her office. “Urchins eat kelp. Otters eat urchins. So when Jim went to places where there were otters, the kelp forests were intact, and all kinds of fish and marine life were thriving.”
Like Estes, Coletti has studied the importance of kelp forests in the Gulf of Alaska. These “forests in the water,” as she calls them, provide nursery habitat for a range of fish and shellfish, offering protection from predators and sequestering so much carbon they play a tangible role in mitigating climate change.
Measuring and monitoring components of nearshore ecosystems, Coletti gained a broad perspective. Intertidal areas were vastly different, and less productive, in the decades before sea otters were reintroduced to the Gulf of Alaska. But urchins, clams and crabs grew in abundance, literally feeding a sea otter birthing boom.
“In [the otters’] absence, the things they eat went crazy, right? There weren’t enough people or industry to make a dent in that [food supply],” Coletti says. “Sea otters, with their high metabolism and constant need to eat to stay warm (because they don’t have blubber), had free reign. Their populations have risen and fallen with the carrying capacity [of their favorite foods]. Plus, as an apex predator, there’s no real harvest of them.”
Coletti says she understands the downside impact of otters, diminishing the ease of gathering shellfish for human consumption. She talks often with Homer boat captain Roarke Brown about this problem, given his contract work with the National Park Service. But she emphasizes that, on balance, her ongoing research — now hampered by federal funding cuts — suggests otters remain a net positive ecologically.
“When it comes to coastal resilience and the importance of biodiversity,” she says, “these animals can help with that more than anything we can engineer. They are simply built for it.”

Are otters at fault?
Mike Booz, an area management biologist with the Alaska Department of Fish and Game in Homer, pins the population growth of sea otters in lower Cook Inlet to the early 2000s, around the time he arrived in the fishing village.
He doesn’t, however, pin the entire blame on growing numbers of sea otters for the diminishing hardshell and razor clams, or king, Tanner and Dungeness crabs.
“In Kachemak Bay, we went from hundreds to thousands [of otters] in my time here,” Booz tells Mongabay. “But before that, from the 1970s to early 2000s, there was a transition already underway in Kachemak Bay and Cook Inlet. It went from being very productive for shellfish to being less productive. At the same time, groundfish like halibut and rock fish numbers grew. Sea otters started popping in on that scene as that was happening.”
Booz adds: “To me, they’re not the cause [of the dearth of nearshore crab and shellfish], or at least it’s not completely clear. Our shellfish stocks were already in decline.”
His observations and research suggest fluctuations in water temperatures driven by climate change have contributed to disrupting the food web, primarily impacting phytoplankton, which shellfish depend on. Less phytoplankton, fewer shellfish.

Between 2015 and 2016, water temperatures grew perilously warm — as much as 5.6° Celsius (10° Fahrenheit) above normal. That’s when a gigantic and persistent mass of globally warmed ocean water in the North Pacific, which scientists dubbed The Blob, also settled into the Gulf of Alaska, harming a range of marine life, especially shellfish.
“Razor clams are filter feeders,” Booz says by way of example. “Years following warmer water temperatures here are terrible for razor clams. There’s no other way to explain [the population decline] other than there is a lack of food for these critters.”
But he doesn’t fully acquit sea otters, either. When shellfish and crabs have a chance to recover in years with colder water, he says, sea otters feast on the bounty of extra food: “I would say things like Dungeness crabs and hardshell clams have no ability to recover to the populations they once were, given the prevalence of sea otters.”
Booz says the otter population is close to its carrying capacity, given its food supply; thus, its numbers will start to level off in the future. In the meantime, he says, greater efforts need to be made in keeping otters away from the numerous small bays and inlets in the Gulf of Alaska so that clams and crabs can propagate.

Otter-proofing with metal netting
Annette Jarozs is the mariculture director at the Alutiiq Pride Marine Institute in Seward, located on the northeast side of the Kenai Peninsula. There, she studies the very species sea otters devour for breakfast, lunch and dinner.
“Going to conferences around Alaska, they [otters] are a very polarizing species,” Jarozs tells Mongabay. “In the last four years, specifically in Prince William Sound, we will go to areas traditionally harvested [by Native Alaskans] for subsistence use — hardshell clams, butter clams, little necks, cockles — and [those areas] look like moonscapes. There are otter pits everywhere. You can’t find a clam bigger than the size of a quarter.”
Jarozs notes how the 9.2-magnitude 1964 earthquake completely changed nearshore marine habitats in the Gulf of Alaska, lifting beaches in some areas by 4.5 meters (15 feet), exposing more shellfish to the newly introduced sea otters. She also mentions the 1989 Exxon Valdez oil spill in Prince William Sound, which coated about 2,000 kilometers (1,200 miles) of shoreline in crude oil and wiped out millions of shellfish, birds and marine mammals (2,000 otters were killed).
But the otters bounced back, and a method was eventually developed to protect recovering shellfish from them. Jarozs describes how her tribally managed institute deployed otter-proof metal mesh netting years ago. Measuring 20 feet by 40 feet and anchored flat on the sand by rebar, the netting deters the marine mammal’s digging and foraging for shellfish in intertidal areas. That method is being tried in a variety of, what she calls, otter exclusion zones.
The nets are working, Jarozs says, though they still aren’t used in many places.
“In one community where we looked at multiple beaches, you could barely find clams of any real size,” she notes. “But where there is netting, you peel it back and it’s the only place we can find large, sizable adult butter clams and little necks. There are otter pits all around the net, but [the otters] can’t get through.”
In some largely underwater areas, Jarozs adds, the netting has created additional habitat as kelp grows up through it, with evidence of fish and crab spawning.
But she makes clear that even widespread use of metal netting can’t be the full response to sea otter predation. Coastal Alaska is far too vast, with sea otters quickly moving on when food becomes scarce, going to where it’s more plentiful.
“For thousands of years, Native people have been part of that chain, really as the top predator,” Jarozs says. “But their role has been arbitrarily reduced [by federal regulations]. Sea otters really are providing important ecosystem services in allowing the kelp to come back. But there has to be a balance.”


Balancing nature and Native Alaskan rights
Raven Cunningham has a vision of just such a balance. Native Alaskan by family and culture, (if not by the hereditary requirements set by the U.S. government), she sees a sensible response to sea otters in sovereign rights and centuries of Native knowledge.
“Native people, since time immemorial, have … been managing their resources,” Cunningham, a Native rights activist with the Native Village of Eyak tribe, tells Mongabay. “You take enough for what you need so that you have more for the next day, the next year. We also understand population dynamics and the importance of a healthy ecosystem.
“That’s been taken away from us, but we are working to get it back,” she adds.
Under the federal Marine Mammal Protection Act, coastal Alaskan Natives have a legal right to harvest sea otters without limit, so long as the pelts are fully used. But there’s a hitch, based on who legally qualifies as Native Alaskan. For more than 50 years, the federal government has defined that qualification by “blood quantum,” requiring at least one-quarter full-blooded native genetics to qualify.
Although Cunningham was raised by parents and grandparents who identified as Native Alaskans, and whose ancestry stretches back centuries, she — and most Natives — fall short under the blood quantum definition, thus legally barring them from otter hunting. In the final month of the Biden administration, that definition was poised for elimination after years of negotiations in which Cunningham participated. Progress stopped when the Trump administration came back into power.

Cunningham says the blood quantum definition was historically intended to restrict Native Alaskan rights, not protect those rights when it came to land and wildlife. As an outspoken advocate for Native rights and educated in natural resource management, she says she represents a consensus of her people when she states:
“The government thinks they have the authority to tell me as a Native person what I can and cannot do. But tribal law is equal to federal law. And my tribe does not acknowledge blood quantum as an identifier of indigeneity. We are pushing down the walls that have kept people like myself from being able to participate in this cultural practice.”
Cunningham lives in Cordova on the eastern side of Prince William Sound. Her part of southeastern Alaska is inhabited by seven Indigenous tribes, and has some of the greatest concentrations of sea otters. She has witnessed their impact, especially on isolated villages without road access, where Natives depend on coastal waters and shellfish for sustenance.
“This area used to be known as the clam capital of the world,” Cunningham explains. “You used to be able to go out into Orca Inlet and harvest 1,000 pounds of Dungeness crab. You were feeding a community. You were eating razor clams. We say, ‘When the tide is out, the table is set.’ Not anymore. I can’t remember the last time I ate a razor clam.”
There’s no doubt things are out of balance ecologically, not just in Prince William Sound, but around the vast sweeping arc of the Gulf of Alaska. However, there’s little consensus on solutions: As Heather Coletti in Anchorage points out, the ecological balance would be worse without sea otters. And as Mike Booz in Homer notes, keeping otters out of select coves and inlets would help protect shellfish, while Annette Jarozs in Seward says spreading more otter-proof netting in intertidal areas will help, too.

In Cordova, Raven Cunningham takes the view that it’s past time to recognize that a big part of the solution lies with Native Alaskans and restoring their full rights to sustainably manage sea otters as they’ve done for thousands of years.
“We are now working on otter management plans,” says Cunningham, who makes clothing, boots and scarves from otter pelts. “Allowing Indigenous people to manage their resources, and having otter harvest management plans for specific regions and tribes, is the resolution to balancing our ecosystem. It’s going to take some time. It’s going to take our knowledge. But it’s also going to take our federal partners and scientists to help us determine what that balance is and what it will take to get there.”
Banner image: A raft of sea otters off the Alaska coast. Image by U.S. Fish and Wildlife Service Headquarters via Flickr (CC BY 2.0).
Justin Catanoso, a regular contributor to Mongabay, is a professor of journalism at Wake Forest University.