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Oregon sea star population suddenly in danger
Oregons sea star population is suddenly imperiled, after scientists found a huge increase in sea star wasting syndrome in the past two weeks.
Oregon State University researchers have found that the ochre sea star, the species most heavily affected by the disease, has been hit so hard it may be headed toward localized extinction in Oregon. Known as a keystone predator, its loss could disrupt the entire marine intertidal ecosystem, researchers say.
This is the first time that die-offs of sea stars, often called starfish, have been identified at one time along such a wide expanse of the West Coast, and the sudden increase in Oregon has been extraordinary, according to researchers.
OSU monitoring of the sea star population found less than 1 percent of the ochre sea stars were affected in April, and only slightly more than that by mid-May.
But by early June an estimated 30 percent to 50 percent of Oregons population had the disease in the intertidal zone.
This is an unprecedented event, says Bruce Menge, a marine biologist at OSU.
We have no clue whats causing this epidemic, how severe the damage might be or how long that damage might last, Menge says. Its very serious. Some of the sea stars most heavily affected are keystone predators that influence the whole diversity of life in the intertidal zone.
Previously, widespread sea star wasting syndrome was observed in British Columbia, Washington and California, but not here.
It wasnt clear why those areas had been hit and Oregon had not, says Kristen Milligan, program coordinator at OSUs Partnership for Interdisciplinary Studies of Coastal Oceans. We were hoping that Oregons coast would be spared, Milligan says. Although it was hit late, we are obviously being hit hard by this potentially devastating syndrome.
In a healthy ecosystem, sea stars attack mussels and keep their populations under control. Without sea stars, mussel populations can explode, covering up algae and other invertebrates. The loss of sea stars also can increase the sea urchin population, which can lead to overgrazing of kelp and sea grass beds.
Past outbreaks of sea star die-offs were associated with warm waters brought by El Niño currents, but water temperatures in Oregon are relatively normal right now.
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