Hakai Magazine

Coastal science and societies

Until the fur trade decimated their populations, sea otters roamed the waters off Oregon. One reintroduction effort failed, but renewed efforts to reintroduce the furry creatures may succeed. Photo by Suzi Eszterhas/Minden Pictures

Otter Bones Provide a Clue to an Enduring Conservation Mystery

Nearly fifty years after a failed reintroduction, a local nonprofit wants to try again—but first, they’re going back in time.

Authored by

by Isobel Whitcomb

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Bob Bailey grew up peering into tide pools and meandering the estuaries of the southern Oregon coast. He loved the region for its richness, its wildness—the rocky inlets, wind-warped cedars, and near-constant barrage of rain. But Bailey never harbored the illusion that Oregon’s coastal environment was pristine. He always knew it was missing a vital component—sea otters.

“I think about what it could be. What it could have been if sea otters hadn’t disappeared,” he says. Sea otters once swam the shores of the entire northern Pacific, from Japan to Baja, Mexico. But a booming fur trade drove up demand for their thick, soft coats; by the 20th century, the species was almost extinct. Now, led by Bailey, a group of environmentalists and biologists—the nonprofit Elakha Alliance—is taking the first steps to reintroduce sea otters to Oregon.

They won’t be the first to try. But before forging ahead, members of the alliance hope to find an answer to a conservation mystery: what caused 93 sea otters introduced to Oregon in the 1970s to disappear?

Between 1970 and 1971, the Alaska Department of Fish and Game plucked nearly 100 sea otters from the remote Aleutian Islands of Alaska, carted them down the northeast Pacific coast, and released them just off of the southern Oregon coast. The project was ambitious and highly experimental, but biologists and locals alike were hopeful that the cute and charismatic creatures would restore degraded marine ecosystems and bolster local fisheries.

For the first few years, the Oregon otters seemed to fare well, says Michele Zwartjes, the recovery director at the United States Fish and Wildlife Service in Oregon. Had you traveled to the coast between 1970 and 1975, you might have seen groups of otters bobbing near the shore, or even mothers swimming with their pups.

But then, unexpectedly, Oregon’s burgeoning sea otter population declined rapidly. By 1981 they were all gone.

“It’s really odd,” says Zwartjes. Based on the first few years of recovery, all signs pointed to the otters’ eventual success, she adds.

Until recently, the best explanation for the otters’ demise is that they tried to swim home. Otters have a strong homing instinct, and become easily disoriented in unfamiliar waters, says Zwartjes. But that hypothesis has a hole. Why would the otters stick around for years without taking off? “It just doesn’t make any sense,” says Zwartjes.

Hannah Wellman, a PhD candidate in archaeology at the University of Oregon, may have found a more compelling hypothesis. Perhaps the otters introduced to Oregon were genetically unsuited to their new environment. Wellman is using ancient otter skeletons to go back in time. By mapping the genetic and physical characteristics of pre-fur trade sea otter populations, her work could help conservationists plan a more successful reintroduction.

“I wouldn’t say my study is the magic bullet,” Wellman says. “But it might be a piece of the puzzle.”

Wellman’s previous research compared tooth sizes between otters from Alaska and Oregon. Now, she’s diving into the differences in their genetic makeup.

Alaskan and Oregonian otter populations are of the same species. But so far, Wellman has found pronounced physical differences between them. For instance, otters from Alaska had significantly larger teeth than those found in either Oregon or California, suggesting that Alaskan and Oregonian otters adapted differently to their environments. That difference could have created problems for the original reintroduction, Wellman explains.

Ronald Jameson, a retired biologist who documented the failure of the 1970 reintroduction, agrees with Wellman.

“You can’t get too much farther away from here than the Aleutians,” Jameson says, “It might’ve been better if we could have brought animals up here from California.” Californian otters would have been a better approximation of the population native to Oregon, genetically speaking, Jameson adds. But at the time of the Oregon reintroduction, California couldn’t afford to lose a single otter. The region’s sea otters had barely survived the fur trade and were still struggling to recover.

“You have all these subspecies and they’re all slightly better adapted to the particular environment that they’re in,” Jameson says.

Perhaps conservationists will take a cue from Wellman’s research and bring otters up from California for their future reintroduction attempt. Today, California’s sea otter populations are much closer to recovery, and some biologists think they’re now viable stock for future reintroductions. But the Elakha Alliance is still far from deciding where to source their otters; Bailey says it could be at least a decade before the reintroduction takes place. The nonprofit is still in the early stages of planning for the reintroduction—garnering local support, communicating with stakeholders, and scoping out ideal habitat.

Solving the mystery of the previous failure is another crucial piece of the planning process.

“That’s one of our challenges, to better understand what happened,” Bailey says. Even so, he recognizes there’s still a degree of unpredictability.

“As I like to tell people,” he says. “Mother nature bats last every time.”