Along the west coast of the United States, impressive populations of green crabs, native to Europe, threaten the entire food chain of fragile coastal ecosystems, from southern California to northern California. Washington. For decades, American authorities have tried to eradicate these crustaceans using methods that are as costly as they are ineffective, but a group of scientists believe they have finally found the solution with sea otters.
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If Elkhorn Slough is much less invaded by green crabs than the rest of the American Pacific coast, it is because this nature reserve in California is home to a group of 120 sea otters. These mammals feed on shellfish and crustaceans, and green crab is one of their favorite meals. They swallow up to 120,000 per year.
In any case, this is the calculation carried out by a group of international scientists who found that the presence of these otters generated astonishing benefits for the ecosystem of the reserve. With fewer green crabs in the water, a species of sea snail, which is their main prey, can grow normally.
Underwater meadows are doing better
These snails in turn eat the algae that blocked sunlight from reaching the seagrass beds. Now, these underwater meadows are doing better and once again serve as a refuge for juvenile fish and food for migratory birds.
Hunted for their fur in the 18th and 19th centuries, sea otters almost disappeared. There are only 3,000 individuals left in California. From the publication of this studyauthorities are considering the reintroduction of sea otters across the entire American West Coast.
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