The feasibility of otters

Two sea otters in the Olympic Coast National Marine Sanctuary. (courtesy photo)

Once abundant along Oregon’s coast, where did the sea otters go?

Aug. 11, 2022 — Centuries ago, a thriving sea otter population swam through a dense network of kelp forests along the Oregon coast. The otters hunted for urchins and crabs, groomed their pups and stored rocks in arm pouches to bust open clams. As they slept, sea otters would wrap themselves in the long kelp strands to keep from drifting away.

Today, that population is nonexistent. There are only two remaining places in Oregon to view sea otters: the Oregon Coast Aquarium and the Oregon Zoo, confined to large aquatic tanks.

While the natural coastal landscapes are no longer dotted with otters, there is mounting evidence that the species once existed in the state. Both Otter Rock in Lincoln County and Otter Point near Gold Beach hold the historic names that the people of the Tillamook and Tututni tribes, respectively, gave the viewpoints.

Records of Oregon-hunted otter pelts sold for small fortunes in the 1800s and early 1900s.

Archaeological evidence dating back 5,000 years shows otter bones mixed along with shell and debris piles near the village sites of Indigenous people, showing the two populations lived together along the coast.

Otters lived in pockets along the coastal stretch from the Aleutian Islands in Alaska to Baja, Mexico, with each coastal language having a unique word for the creature.

Despite the historical presence of sea otters in Oregon, the potential return is complicated.

The indigenous-led Elakha Alliance, elakha” being the Chinook trading word for sea otters, is leading the efforts to research the feasibility of reintroducing the species to the state. The alliance believes in a vision of the Oregon coast 50 years from now, with humans coexisting alongside a thriving otter population and robust ecosystem.

There are not any current plans to reintroduce sea otters back into Oregon, but Elakha is taking the first steps towards the years of needed research.

On July 27, the U.S. Fish and Wildlife Service (USFWS) released their study Feasibility Assessment: Sea Otter Reintroduction to the Pacific Coast,” which drew from the work of Elakhas team of scientists.

While reintroduction has been found to be feasible, additional information and stakeholder input are needed to help inform any future reintroduction proposal, the USFWS study said.


Where did the otters go?

The reason for the species' disappearance is simple, and a recognized part of the states history. Coveted for their dense fur coats, trappers hunted otters to near extinction.

Sea otters, unlike other marine mammals that rely on thick layers of blubber, boast a thick coat to stay warm, with around a million hairs per square inch. The average human has only 100,000 hairs, one tenth of that, on their entire head.

This thick layer creates a layer of oxygen, impenetrable by water, that allows the innermost fur layer to stay dry, and the otters body to stay warm. Otter pups, who are unable to swim, are groomed by parents to the point of floating on water.

While a useful adaptation for the species, the dense, soft pelt was desired by humans. Sea otter pelts became an international commodity during the fur trade of the 18th and 19th centuries.

According to reporting by The Oregonian, records show that the last wild sea otter was killed in 1906 and sold in San Francisco for $900. In Washington, the last otter was killed four years later in 1910. The pelt of the latter was sold for $1,000, or approximately $27,000 today.

It wasn't until 1911 when the international Fur Seal Treaty was passed, the first legal protection for sea otters. At the point of the treaty, only pockets of sea otters existed in remote locations, with estimates of less than 1,000 otters surviving. All living sea otters today are descendants of these few survivors.

Today, the only otter sightings in Oregon are of a lone drifting male, exploring a new territory, only to disappear soon after.


The Ecological Impact

With the disappearance of the sea otter came the gradual destruction of the lush kelp forests that marked the Oregon coasts.

Otters are a keystone species,” said Amy Hash, a supervisor of the marine area at the Oregon Zoo. Much like the keystone of a bridge, the sea otter held the ecosystem together. In their absence, the coastal system has suffered.

Kelp forests, with long stalks as tall as trees, contribute to the health of the shoreline and sequester carbon from the atmosphere. Without sea otters present to keep the urchin population in check, the spiky creatures devoured every stalk, blade or bulb of seaweed and kelp around. The result is what is known as an urchin barren,” as the urchin population grows without natural predators.

When trappers killed the last otter, they killed the kelp forest along with it.

“Our kelp forest habitat is no longer as strong and healthy as it once was,” Hash said. You can still find kelp habitat along the Oregon coast, but at one time, it was much more robust.”

According to the Oregon Marine Reserves, the abalone population in these locations is also diminishing, as the marine mollusk is reliant on a thriving kelp population as well and is being outcompeted by the urchins.

Urchins, on the other hand, can survive for years without food.

The urchins’ lack of kelp has caused one distinct biological change. While the urchin roe, or uni,” is edible and sought after in sushi dishes worldwide, urchins harvested from barrens have little to no commercial value. After a long period without food, the urchin survives by degrading and shrinking its reproductive organs, creating poor quality uni, according to the Oregon Marine Reserves.

After a widespread disease among sea star populations, combined with the effects of increasing ocean acidification as the temperature rises, the urchins remain unchallenged, eating any and all kelp that remains.


Previous Attempts of Relocation

In 1970, as an attempt to remove the sea otters from the nuclear weapon testing in the Aleutian Islands, an effort to bring the species back to the west coast was undergone.

According to The Oregonian, 29 sea otters were flown into the Port Blanco Coast Guard airstrip and towed out in a floating pen to the Redfish Rocks marine reserve in southern Oregon.

The next year, 64 more sea otters were introduced off of the Oregon coast.

While the first couple years were optimistic with the presence of otter pups among the few dozen remaining, the numbers started to dwindle.

Ron Jameson, who monitored the otter population as a graduate student at the time, estimated that only a third of the otters remained after the second year.

By 1982, Oregon had lost its sea otter population for the second time.

Despite the presence of suitable habitats and food sources, the sea otters had mysteriously disappeared.

In a 1971 New York Times article about the relocation effort, it was estimated that between 900 and 1,100 sea otters died during the capturing and release process, although this accounts for all efforts along the West Coast.

A small population relocated to the coast of Washington continues to thrive to this day, though.

After 59 otters were transported to the tip of the Olympic Peninsula, an estimated 10 survived. But once the population stabilized, it began to grow.

According to the Washington Department of Fish and Wildlife, the states sea otter population, descending from those 59, was around 2,800 in 2019.

“Translocation success depends on a variety of recognized factors: the appropriate number and health of founding individuals, suitable habitat, adequate food resources, and realized reproductive potential and survival rates,” the Elakha study reads. The feasibility of reintroducing sea otters to the Oregon Coast must include a comprehensive review of prior sea otter translocations and an evaluation of specific translocation goals.”

The study concluded that a lack of understanding sea otters led to the failures of past translocations, but given suitable habitat, prey resources, and protection from human or other mortality sources, sea otters can survive and thrive following translocations.”

Successful translocations undergo an establishment phase,” in which the population shrinks to a small fraction, from 10-50%, due to emigration and mortality.

When successful, though, sea otters play an important role in restoring coastal marine ecosystems and recovering genetic diversity.


Potential Economic Impact

While the feasibility study has indicated potential success, much more information is needed before any plans are made. A big concern is with the impact that sea otters could have on the fishing, crabbing and clamming industries.

Sea otters have very high metabolisms and need to eat around 25% of their body weight in food every day.

For a 40-pound otter, the average size of a female, Hash said, she would need to eat 10 pounds of food in a single day.

“In zoos and aquariums, they eat clam, crab, mussels, fish, shrimp, urchins and squid as a staple,” Hash said. In the wild, clam is the most preferred diet item.”

This could pose some competition with fisheries, specifically with clamming and crabbing.

The Elakha Alliance study said that invertebrate fishing of Dungeness crab, red rock crab, razor clams, butter clams, Gaper clams, littleneck clams, cockles, mussels, ghost shrimp, and red and purple sea urchins, commercially and recreationally, could potentially face impacts.

“Some of these fisheries represent hundreds of thousands of dollars annually, or even, in the case of Dungeness crab, tens of millions of dollars to the Oregon economy,” the study stated. Thus, the potential economic impact of even a small reduction in fishery landings because of sea otter recovery is consequential.”

It can also vary by location. In Alaska, sea otter recovery was associated with negative impacts in Dungeness crabbing. In California, however, there was a positive correlation between sea otter recovery and crab landings.

“It really depends on where they are, where theyre introduced, what the population level looks like, how fast the population increases,” said David Fox of the Oregon Department of Fish and Wildlife. There are so many variables.”

In Oregon, Dungeness crabbing typically happens up to depths of 600 feet, Fox said. According to the National Parks Service, sea otters typically dive between 5 to 60 feet to find food to maximize caloric intake, although they can dive to depths of 250 feet.

Since the past century of commercial invertebrate fishing had emerged without the competition of sea otters, the Elakha Alliance said that engaging in a constructive dialogue with all affected stakeholders and community groups” will be a fundamental part of the decision making process.


Could Sea Otters Return to Oregon?

The first steps have been taken to return sea otters to their historic landscape, but the effort will take years before any final decision is made.

Reintroducing sea otters back into the Oregon coast would have a plethora of direct and indirect impacts, ranging from potential competition with fisheries to the gradual return of the kelp forests and increased biodiversity.

The reintroduction of the species is likely to succeed, but with the appropriate considerations, the Elakha Alliances study found. The USFWS backed up these findings.

For the future, the USFWS recommends convening a series of structured decision making workshops with scientific experts and key stakeholders to explore reintroduction options, including the identification of potential reintroduction sites.

It also recommends initiating a rigorous socioeconomic impact study to look at potential negative and positive local impacts, developing plans for pilot studies or small-scale experimental reintroductions to resolve key uncertainties in reintroduction methods and integrating existing Oregon and California population models.

For more information on both feasibility studies, visit or