The reef's most feared starfish may quietly keep it healthy

Crown-of-thorns starfish, the spiny coral eaters blamed for wrecking swaths of the Great Barrier Reef, may quietly keep it healthy when their numbers stay low, according to University of Sydney research published in Ecology and Evolution. A team led by Dr. Shawna Foo examined feeding scars at the One Tree Island Research Station, inside protected zones where fish keep starfish populations in check. Living coral tissue survived nearly 75 percent of the feeding events they observed. The starfish, it turns out, eat a consistent amount and move on rather than demolishing an entire colony. By grazing on fast-growing Acropora, they open space for slower species like Montipora and Porites. "Once an outbreak is suppressed, the goal should not necessarily be to eliminate COTS entirely," Foo said. Co-author Professor Maria Byrne tied it to the intermediate disturbance hypothesis, the idea that ecosystems can benefit from a little moderate trouble. The reef's most feared diner, it seems, knows when to stop.