From Environment America (https://environmentamerica.org/):
In nature, everything is connected — and nowhere is that clearer to see than with 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.1
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 our country’s wildlife and the natural balance they help keep in place.
To understand what we lose when we lose the sea otters, we have to 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.2
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.3
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.4
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.5
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.6
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.7
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.8
To save the Pacific’s kelp forests, we need to restore the forests’ best protectors.
Environment America is 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.
- Steve Blackledge, “Let’s bring back the southern sea otter to the Pacific Coast,” Environment America, October 25, 2022.
- “Kelp Forest Habitat on the West Coast,” NOAA Fisheries, November 2, 2021.
- “Kelp Forest Habitat on the West Coast,” NOAA Fisheries, November 2, 2021.
- “What lives in a kelp forest,” NOAA National Ocean Service, September 25, 2022.
- “What lives in a kelp forest,” NOAA National Ocean Service, September 25, 2022.
- Lisa Johnson, “Kelp is disappearing from parts of the West Coast. These scientists are trying to save it,” CBC News, December 4, 2022.
- “Southern Sea Otter,” Marine Mammal Commission, last accessed December 19, 2022.
- “Southern Sea Otter,” Marine Mammal Commission, last accessed December 19, 2022.
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