Sea otters’ appetite for crab is helping strengthen estuary banks
Sea otters, once hunted to near extinction, are staging a comeback in California. Their return has revealed the incredible positive effects these furry apex predators can have on the state’s coastal ecosystems, including kelp forests and seagrass meadows. Now, there’s another coastal ecosystem to add to that list, one that plays an important role in bank stabilization, water filtration, and carbon storage: the salt marsh. In a new study in Nature, researchers found that sea otters have reduced bank erosion rates by 69% in Elkhorn Slough, a coastal wetland south of San Francisco, in the decades since their return to the estuary. Their big effect is due to their big appetites—the Elkhorn Slough salt marsh has been eroding, in part, because of root-munching shore crabs that burrow into the soil and destabilize the banks.