Nature

Perspective | Sea Otters in San Francisco?


Ever because the Nineteen Thirties, when an unbelievable remnant colony of sea otters was found off the rugged Massive Sur coast after greater than a century of intensive fur looking, Californians have labored to convey the animals again from the sting of extinction. Their numbers have grown from round 50 people to somewhat underneath 3,000, the place the inhabitants has hovered for some years, remaining threatened underneath the Endangered Species Safety Act. Whereas the otters now not face imminent extinction, a rising motion to convey them again to northern California waters may spell revitalization not only for these furry mammals however for total communities of life—our personal included, as Californians collectively look towards coastal ecosystems for local weather options.

For hundreds of years, sea otters have been the keepers of kaleidoscopic communities of life alongside the California coast. Otters plucked and ate kelp-grazing urchins, and the kelp grew steadily, harboring a stunning variety of life from tiny invertebrates to fats harbor seals. The ocean otters’ near-extinction within the early 1900s meant not simply the potential extinction of a single species, however the extinction of ecological interactions—the extinction of relationships. Even now, within the locations the place sea otters stay regionally extinct, marine heatwaves and mass sea star die-offs have toppled the ecological stability of kelp forests—95 p.c of California’s kelp stands have disappeared within the final 10 years—whereas in locations the place otters have returned, they’ve boosted the well being of surviving remnant kelp patches.

For the final 5 years, the California sea otter inhabitants has held regular or barely declined on the central coast. However the otters haven’t been in a position to develop their vary past the core area from San Mateo County south to Santa Barbara County, and their present numbers are nonetheless far under what is critical for a very sustainable inhabitants. Now, current analysis on otters’ ecological interactions reveals a pathway to assist them develop into their former territory.

In 2013, Sonoma State College biologist Brent Hughes found a connection between sea otters and the seagrass beds he was finding out in Monterey Bay’s Elkhorn Slough. In locations with excessive ranges of nitrogen from agricultural runoff, algae will start rising on seagrass, stopping it from photosynthesizing and ultimately killing it. An invertebrate known as Taylor’s sea hare helps graze the algae down. “These animals are superb,” Hughes says in a current webinar hosted by Marine Conservation Institute, exhibiting a photograph of a small sea slug with inexperienced dappling throughout its physique. “They’re like little lawnmowers.”

taylor's sea hare
A Taylor’s sea hare (Phyllaplysia taylori) on an eelgrass blade in Elkhorn Slough. (Photograph by Quinn Jonas, iNaturalist CC)

Hughes’ examine confirmed that eelgrass in Elkhorn Slough had began to rebound—regardless of heavy nutrient hundreds and excessive algal blooms—proper across the similar time that sea otters have been being reintroduced to the estuary. It turned out the ocean otters have been devouring the native crabs, which have been predators of the ocean slugs and different algae-eating invertebrates. By maintaining the crab populations in verify in order that the “lawnmowers” may do their work, otters have been reviving eelgrass ecosystems. A follow-up examine by Hughes’ crew demonstrated that seagrass beds develop within the presence of sea otters, and in 2021 Hakai Institute launched a paper exhibiting that sea otters improve the genetic variety of seagrass.

As in any good relationship, the advantages are mutual: otters assist seagrass beds thrive, and in flip seagrass helps otters, offering wealthy meals and restful habitat the place otters can escape sturdy currents and huge ocean predators like sharks. “Of the habitats out there to otters,” says Hughes, “the very best focus of sea otters in California is in Elkhorn Slough, and inside that habitat the very best focus is in seagrass beds.”

When he acquired a Metz Fellowship for conservation, Hughes was in a position to springboard off of his observations in Elkhorn Slough, exploring how sea otters would possibly affect different estuaries elsewhere in California. In 2019, Hughes and several other colleagues revealed a examine suggesting the estuarine habitats in San Francisco Bay may theoretically assist as many as 6,000 sea otters. This report is spurring a rising motion to return otters to their historic vary within the San Francisco Bay Space—a motion that would revive not simply otters however total ecosystems.

sea otter illustration
(Illustration by Gena Bentall, Sea Otter Savvy)

If sea otters and seagrass meadows thrive collectively, what’s maintaining the otters from taking issues into their very own paws and pushing additional into their previous estuary territories? Between their present vary and the estuaries of Northern California, “there’s not plenty of kelp habitat for them to make use of as migratory jumps from kelp patch to kelp patch,” Hughes explains, “so there’s not plenty of alternative to search out refugia from nice white sharks.” Heather Barrett, the science communication director for the nonprofit Sea Otter Savvy, which works to scale back human-otter battle, describes the coastal journey northward as a “shark gauntlet” that bars the doorway to estuaries in Northern California.

Biologists have additionally discovered that otters are terribly “website loyal,” which signifies that it’s difficult to pluck them up and set them down in a brand new location. In 1987, an experimental translocation program started on San Nicolas Island, the place otters have been relocated to the distant Channel Islands from the mainland California coast. Although a small inhabitants of sea otters stays there right this moment and is progressively rising, most otters returned to their unique territory, resulting in the translocation program being terminated in 2012. Nonetheless, younger otters usually tend to persist with a brand new territory, and a groundbreaking program on the Monterey Bay Aquarium has succeeded in releasing greater than 35 orphaned otters into Elkhorn Slough. Right here, the rescued pups—which have discovered find out how to succeed as otters from surrogate otter moms on the aquarium—have survived simply in addition to their wild counterparts, and so they now account for almost all of otter inhabitants progress within the slough during the last 15 years. It’s a hit story that would simply scale up as soon as the fitting items are in place.

And the items, it appears, are starting to click on into place. “Ahead momentum proper now’s big,” says Andrew Johnson, who spent 20 years pioneering the Monterey Bay Aquarium surrogacy program and now works with Defenders of Wildlife. In Oregon, an Indigenous-led nonprofit known as the Elakha Alliance is evaluating the feasibility of bringing sea otters again to the Oregon Coast. On the similar time, Congress has ordered the U.S. Fish and Wildlife Service to discover sea otter reintroduction as a species administration technique throughout the broader West Coast. Longtime otter biologist Tim Tinker spearheaded the Elakha Alliance feasibility examine and is now additionally serving to to advise the report for the California Division of Fish and Wildlife. The synchronicity of those two efforts—and the congressional strain to complete the West Coast report this 12 months—brings the query of otter vary enlargement into close to focus after years of sluggish groundwork.

In the meantime, Johnson has been in dialog with the Aquarium of the Pacific and SeaWorld to coordinate preliminary planning for brand new surrogacy services for orphaned otter pups, though Covid-era funding priorities have slowed the work. If established, these services may assist increase extra orphaned pups than the Monterey Bay Aquarium can handle alone—pups which may, theoretically, be launched into new estuaries when the time is true. “I believe it’s all going to hinge on surrogacy,” Johnson says. “Persevering with to take a passive strategy could by no means obtain restoration of the inhabitants, no less than not in our lifetimes.”

A sea otter swims previous cyclists on the Sausalito-Mill Valley path in 2015. The younger male otter spent a number of weeks in Richardson Bay earlier than dying of domoic acid intoxication and parasitic an infection. (Photograph by youtube person NorthwesternPacificHistoryIsCool)

If otters are reintroduced into their historic vary, the place will they stay? Though Hughes’ 2019 examine means that San Francisco Bay may maintain big numbers of sea otters (and traditionally it did, as otter bones present in middens from Indigenous village websites alongside the Bay recommend) the truth of bringing otters into the Bay is sophisticated. Excessive delivery site visitors, nearshore improvement, and poisonous ranges of city air pollution would possibly make it a tricky entry level for younger otters. Hughes and Tinker are working to develop fashions that may predict how effectively smaller Bay Space estuaries like Drakes Estero and Tomales Bay may assist otter populations, and Jane Rudebusch, a current graduate of Hughes’s lab, has designed a map that analyzes potential sea otter reintroduction websites by overlaying promising habitat throughout a myriad of danger elements, from Indigenous clamming websites to areas with excessive boating site visitors.

Returning sea otters to locations the place they’ve been lacking for 100 years is an advanced dialog. The larger Bay Space is a unique place than it was a century in the past—folks from all walks of life rely on the coast for his or her livelihoods, from oyster farming to outside recreation. Any challenge that strikes ahead with sea otter reintroduction might want to honor these sophisticated layers of trade and financial system; with out consensus, vary enlargement plans are more likely to stumble. The nonprofit Sea Otter Savvy is presently gathering suggestions in a stakeholder survey, which could be discovered on their web site.

Voices from all sides are necessary: in Southeast Alaska, the profitable return of northern sea otters to a lot of their historic vary has sparked debate and frustration amongst fishermen who argue that the otters compete for profitable urchins and shellfish—no small inconvenience, in an trade valued at $10 million. Nonetheless, Hughes says, “what we’ve seen up north is that otters regenerate habitat” in a method which may bolster biodiversity to profit each ecosystems and economies. “They eat urchins and convey again kelp, and so they would possibly offset any unfavorable results on fisheries.”

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Within the time forward—a time punctuated not simply by the doable return of a keystone predator, but in addition by marine warmth waves, storm surges, ocean acidification, and different local weather disruptions—trying towards the way forward for fisheries will seemingly be a essential reckoning, no matter the place sea otter vary expands. The ocean is overstrained, and whereas sea otters can do lots for us, we’d additionally have to redefine what’s sustainable for ourselves and future generations on the California coast. It appears that evidently the fitting order of operations is to heal first, and to discover a new stability afterward.

sea otter in Monterey
A sea otter in Monterey Bay. (Photograph by Morgan Rector)

It is very important observe that the return of sea otters to northern California can’t be simplified as a return to the way in which issues have been. It’s doable, as an alternative, that otters would possibly assist us handle the way in which issues are. Intact ecosystems—specifically, intact ocean ecosystems—play an unlimited function in mediating the results of local weather change. Research point out that coastal ecosystems sequester ten instances extra carbon than tropical forests, and may maintain that carbon for millennia longer than terrestrial ecosystems can. However these “Blue Carbon” habitats are among the many most endangered ecosystems on the planet. We’re shedding virtually two p.c of seagrass meadows yearly—two soccer fields value each hour. If otters can revive estuaries elsewhere alongside the California coast as effectively as they’ve rebalanced Elkhorn Slough, then they could be not solely ecosystem architects, however “unsung local weather heroes,” too, says Marine Conservation Institute President Lance Morgan. Right here on the West Coast, the place the results of local weather change are more and more seen and visceral, that is no small factor.

Treating our coastal ecosystems not simply as casualties however as lively brokers in tackling local weather disruption requires an act of reimagining. In restoring this misplaced stability, it appears now we have the chance to summon not simply an previous world, however a greater one.

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