What happens when the Pacific loses its otters?

Without sea otters, entire ocean ecosystems are at risk.

Kedar Gadge via Unsplash | Public Domain

Update: The U.S. Fish and Wildlife Service announced on Sept. 19 that southern sea otters will retain protections under the Endangered Species Act. Learn more about the next steps needed to protect sea otters.

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In nature, everything is connected — consider the disappearance of the Pacific sea otters.

A couple hundred years ago, sea otters were plentiful along the Pacific coast from Mexico to Alaska, and coastal ecosystems thrived. But by the early 20th century, otters had been hunted to extinction across more than 85% of their original habitat.

All sorts of marine species are still struggling as a result.

The loss of this keystone species has allowed sea urchins to run amok and destroy the kelp forests that are crucial for everything from shrimp to whales to our climate.

Learning about the sea otters — and what happens when we lose them — can teach us a lot about the importance of wildlife and the natural balance they depend on and help keep in place.

Sea otters are crucial to our ocean ecosystems

To understand what we lose when we lose the sea otters, let’s look at their habitat.

The shallow waters of the United States’ Pacific coast have traditionally been home to vast kelp forests. Composed of underwater fields of kelp, these forests have formed the foundation of rich marine ecosystems from Baja California to Alaska.

The kelp themselves can grow up to 200 feet long, with small air-filled pods that help them rise to the surface and form a canopy to photosynthesize. Down below, the kelp anchors itself onto rocks on the ocean floor.

When their numbers grow, the individual strands of kelp form a forest that slows ocean currents and provides a calm space in which a vast range of animals find shelter. Everything from crabs to sea lions to whales make their home in the forests.

And floating above and swimming through it all is the sea otter.

For the otters, the kelp forest is a shelter from violent ocean storms and predators like orcas and sharks. In turn, the otters act as guardians of these marine forests, eating the sea urchins that like to chew on the kelp.

And without their guardians, these forests have been suffering.

Without the otters to keep them in check, the sea urchins eat through kelp forests out of control, replacing the lush landscape with what are called “urchin barrens.” These barrens provide none of the shelter that the vegetation did. And while the urchins carpet the floor, kelp struggles to reestablish itself, depriving all the animals that rely on the forests for their homes.

This is a problem that has been plaguing the Pacific coast since overhunting decimated otter populations. At their lowest point, only around 50 sea otters survived along the coasts of central California.

The sea otters’ numbers have risen since their lows of the early 20th century, but they’re still a fraction of what they were before they were hunted.

To save the Pacific’s kelp forests, we need to restore the forests’ best protectors

We’re working to protect wildlife and the habitats they need, like the sea otters and the kelp forests.

When we remove one species, a ripple effect touches dozens of species beyond it and even entire ecosystems. But by the same measure, when we restore missing species, we can help put our planet’s ecosystems back into balance.

All the work we do at Environment California is made possible by supporters like you. It’s your generous donations that allow us to keep standing up for our country’s wildlife and wild places and work to protect crucial species like the sea otters. Will you donate to help support our work?

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Frequently asked questions about sea otters

Why are sea otters disappearing?

In the 1800s, fur traders hunted the otter to near extinction across more than 85% of their original habitat. At their lowest point, only around 50 sea otters survived along the coasts of central California. The sea otters’ numbers have risen since their lows of the early 20th century, but they’re still a fraction of what they were before they were hunted.

Are Pacific sea otters endangered?

We hope to soon see the day when the otter doesn’t need the protections of the Endangered Species Act, but we’re not there yet. The Fish and Wildlife Service set a target population of 3,090 otters. One can argue that the number is too low, but even so, the otter’s population isn’t yet stable. It’s bobbing above and below the target population. The agency estimated the population at 3,272 in 2016. The count declined to 3,186 otters the following year, and it fell again to an estimate of 2,962 otters in 2019, with no count in 2020. Until the population is stable and above the target, the otter still needs our help.

Why is the sea otter considered a keystone species?

Otters once ranged from Baja, Mexico to Alaska, but with their absence in many areas, ecosystems have gotten severely out of whack. Otters are eaters, and they eat lots of urchins. Urchins eat sea kelp. Without the otters to keep them in check, the sea urchins eat through kelp forests out of control, replacing the lush landscape with what are called “urchin barrens.” These barrens provide none of the shelter that the vegetation did. And while the urchins carpet the floor, kelp struggles to reestablish itself, depriving all the animals that rely on the forests for their homes.

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Authors

Steve Blackledge

Senior Director, Conservation America Campaign, Environment America

Steve directs Environment America’s efforts to protect our public lands and waters and the species that depend on them. He led our successful campaign to win full and permanent funding for our nation’s best conservation and recreation program, the Land and Water Conservation Fund. He previously oversaw U.S. PIRG’s public health campaigns. Steve lives in Sacramento, California, with his family, where he enjoys biking and exploring Northern California.

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