Originally published September 29 2014
What's killing all the sea stars along the West Coast?
by Julie Wilson staff writer
(NaturalNews) Millions of sea stars have mysteriously been wiped out along the Pacific coast, stretching from Alaska all the way to Mexico. Sea stars, belonging to the class Asteroidea, have been around for 450 million years, according to researchers. More than 20 species of sea stars are showing signs of what experts call "wasting syndrome," a condition causing the ancient star's limbs to disintegrate and melt, resulting in massive die-offs.
Last November, divers off the coast of Washington were able to catch video footage of the diseased starfish, describing the melting process as beginning with a "strange loss of coordination and inability to grasp onto objects." Their limbs and insides eventually began to fall apart, piling on top of each other, creating heaps of dead sea stars.
"They are dying -- wasting away, drying out and disintegrating into sun-bleached piles of dust. Limbs detach from the body and seem to melt away," reported The Islands' Sounder.
Researchers have known about the recent die-offs for about a year, but the cause is still unknown
"We have evidence that an infectious agent is involved, but it is too soon to say yet whether it is a virus or a bacterium," said Drew Harvell, a marine epidemiologist at Cornell University.
"It's the largest mortality event for marine diseases we've seen. It affects over 20 species on our coast and it's been causing catastrophic mortality," added Harvell, who has specialized in studying outbreaks among coral reef invertebrates.
In the San Juans, a group of four islands off the coast of Washington, biologists discovered that 49 percent of the sea star population is diseased and dying. The disease moves quickly. When experts first examined ochre sea stars near Indian Island, they noted only 10 percent to be sick, but just weeks later found that number to have multiplied five times.
More than 40 expert biologists from West Coast universities and surrounding aquariums are intensely studying what could be the cause of wasting syndrome. "This is slow, careful work that takes repeated experimentation in the lab and many tests to verify," Harvell said.
In regard to extinction, she added, "We expect the stars to recover. But this is such a big, widespread event, it could take a long time."
Experts suspect that warming waters could be contributing to the sea star's stress, making them more vulnerable to pathogens. Pockets of cold water and swift currents have protected the region until recently, Harvell told PBS NewsHour.
"Over this winter I surveyed here, and looked at every animal and there was no disease at all," said Morgan Eisenlord, a Ph.D. student in Harvell's lab at Cornell. "When we came back in the spring we found sick animals so it obviously spread as it started to get warmer."
If a pathogen is the cause, some believe it's concentrated in mussels, which pass it on to starfish when eaten. Strangely, both captive and wild starfish living in the rocks along Santa Barbra, Calif. showed signs of illness simultaneously.
Indoor tanks for starfish at the University of California Santa Barbara Aquarium are filled with filtered seawater. One tank was fed mussels harvested from the rock outside, and the other frozen squid. Starfish fed frozen squid remained healthy, while the ones fed mussels developed wasting syndrome.
The small sample size has prevented researchers from jumping to conclusions, but experts feel further research on the hypothesis is warranted. Scientists at Cornell have narrowed down a list of pathogens which they suspect could be responsible, and expect to publish their research in a scientific journal.
So far, warmer waters, pathogens and radiation resulting from the aftermath of the Fukushima meltdown have been blamed for sea star die-offs, but until the completion of more research, an answer is unlikely.
Without sea stars, the fate of aquatic ecosystems is unknown. These intertidal apex predators are considered a "keystone species," whose extinction would most likely have a domino effect on oceanic biodiversity.
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