ARI SHAPIRO, HOST:
Let's talk about sea otters. They float on the water, cuddle their little babies. Same time, they're voracious eaters that gobble up shellfish. And that has brought them into conflict with people who rely on shellfish for their livelihoods. NPR's Nell Greenfieldboyce reports that scientists have now assessed the economic impact of restoring sea otters to their historic homes.
NELL GREENFIELDBOYCE, BYLINE: Sea otters are pretty big. They can weigh 60 pounds or more. To survive in the cold waters of the Northern Pacific, they need to eat a lot.
JANE WATSON: And so a sea otter is going to eat about a quarter of its body mass, its body weight, in food each day.
GREENFIELDBOYCE: Jane Watson is a researcher with Vancouver Island University in Canada. She says historically sea otters coexisted with Indigenous people. But when the Europeans arrived, hunters with the fur trade wiped the otters out.
WATSON: All of a sudden, all of the prey that otters eat no longer had their principal predator eating them anymore.
GREENFIELDBOYCE: Clams, crabs, sea urchins - their populations took off, and people got used to the abundance. Well, a few decades ago, sea otters were reintroduced to the west coast of Vancouver Island. Edward Gregr is an ecologist at the University of British Columbia. He says further down the coast from where the otters now live, there's another spot where the otters haven't yet moved in.
EDWARD GREGR: And so we thought, you know, this is a perfect natural experiment to compare what the ecosystem looks like with and without sea otters.
GREENFIELDBOYCE: In the journal Science, they say otters do eat up clams and crabs worth millions of dollars. They also devour sea urchins, and that allows kelp to flourish. The kelp supports fish species that are worth a lot of money. What's more, tourists will pay to watch the otters frolic. Gregr says, all in all, the financial benefits of otters are more than seven times greater than the losses. But, he says...
GREGR: We want to make sure we don't lose sight of the caveats around that, mainly the fact that, you know, these costs and benefits are not going to be distributed equally across fisheries or communities.
GREENFIELDBOYCE: Tourism, for example, isn't necessarily a realistic or attractive option for people who live in remote areas where access to food is a real issue. Barbara Wilson is a member of the Haida Nation who's studied Indigenous people's feelings about the sea otters.
BARBARA WILSON: Because they eat the same foods as we do, the impact for us is fairly critical.
GREENFIELDBOYCE: She says Canadian law currently protects the otters.
WILSON: So we can't hunt them. We can't manage them the way our ancestors did.
GREENFIELDBOYCE: She says the otters have a right to eat, but so do people.
Nell Greenfieldboyce, NPR News.
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