Sea otters in California have undergone a “stunning comeback” in population numbers since their near-extinction in the mid-20th century. These coastal mammals are famously adorable, but did you know they’re also good for ecosystem infrastructure?

In a new story from NPR, University of Florida coastal ecologist Christine Angelini spoke about a restoration project in Monterey Bay, California, about an experimental ecosystem shift. Sea otters enjoy snacking on burrowing shore crabs, which in large numbers can destabilize banks and shorelines. The researchers, Angelini as well as Brent Hughes from Sonoma State University, placed experimental cages to keep sea otters out of a test shore site, but allow crabs to move freely.

The experiment ran for three years, and the results were clear: Crabs created more burrows and ate more vegetation, causing erosion to the shoreline. When otters were allowed in, they kept the crab populations in check and the marsh was able to quickly stabilize.

“By the study’s end, they were preventing 10 or so inches of salt marsh loss per year,” said Ari Daniel, NPR science reporter.

Listen to the interview or read the transcript here to learn more about the experiment and subsequent paper.

Featured image: Timothy Wells-DeTone via


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