California researchers find sea otter population helps stop invasion of green crabs
Though sea otters are an unofficial mascot of Monterey County and popular among tourists and locals alike, they are also described as voracious predators that help keep problematic invaders out of coastal waters.
A study was in the journal Biological Invasions, detailing that otters at the Elkhorn Slough are keeping populations of globally-invasive green crab at bay.
"I've studied green crabs in estuaries on three coasts and two continents for decades, and this is one of the first pieces of good news we've gotten," said Rikke Jeppesen, an estuarine ecologist at Elkhorn Slough National Estuarine Research Reserve who spearheaded the publication, in a statement.
Green crabs were first found at the slough in 1994 and the population peaked in the early 2000s. Since then, the population has declined and hasn't reached peak numbers again.
Meanwhile, the population of sea otters has risen. Sea otters were recovering from near extinction in California in the early 2000s.
The new study is first-time evidence that the recovery of the otters is benefiting the overpopulation of invasive species.
Investigators for this study used data on otter foraging to calculate that up to 120,000 green crabs could be consumed each year by the current sea otter population.
"We set traps and are delighted that we no longer catch large green crabs," Jeppesen said in a statement. "This is one more great reason to support recovery of top predators in coastal habitats."
More information: Rikke Jeppesen et al, Recovering population of the southern sea otter suppresses a global marine invader, Biological Invasions (2024).
Journal information: Biological Invasions
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