November 4, 2013
Mysterious Wasting Bacteria Killing Starfish Along West Coast
Brett Smith for redOrbit.com - Your Universe Online
California marine biologists are reporting the spread of a mysterious bacteria that is killing starfish up and down the West Coast – transforming the echinoderms into piles of goo in the process.
The affected animals form white lesions on their exterior that grow and occasionally turn ulcerous. The starfish begin to lose arms and, after a few days or weeks, dissolve into what some have described simply as “goo.”
The disease, known as sea star wasting syndrome, has been seen in the past, but not at the rate observed during the current outbreak. Thought to be caused by a bacterium, scientists are trying to determine why the syndrome is spreading the way it is this year.
According to a recent report from UC Santa Cruz, ten different species of sea star have been affected with the disease and 95 percent of starfish in some coastal areas have been devastated. Scientists at the university are tracking reports of the disease, which has been seen as far north as Alaska and as far south as Santa Barbara, Calif.
“We've never seen it at this scale up and down the coast,” Raimondi said.
Anecdotal evidence points to something in the water as starfish in an aquarium at the Gulf of the Farallones National Marine Sanctuary visitor center at the San Francisco Presidio died from the syndrome in September. The tank was filled with water pumped in from the ocean, which did not affect the other organisms – such as eels and anemones – living in the aquarium.
Steven Morgan, an environmental science professor at the Bodega Marine Laboratory, told The Press Democrat that he saw some gaunt sea stars on the rocks at Schoolhouse Beach near Bodega Bay two months ago. Unfortunately, he didn't collect samples and couldn't substantiate if they had the wasting syndrome.
“It was a strange anomaly,” Morgan said. “None of us had ever seen anything like this before.”
While large groupings of the disease were seen near Santa Cruz, Monterey and Santa Barbara, Raimondi said the data probably under-represents the degree of the disease outbreak, which was first spotted over the summer in Washington.
According to The Press Democrat report, the syndrome primarily affects one species, Pisaster ochraceus. The orange and purple starfish inhabit California tide pools and play a major role in their biodiversity. The so-called ‘keystone’ species eats marine mussels and if the starfish are wiped out, the tidal mussels could proliferate and crowd out other species, Raimondi said.
The disease struck Southern California in 1983-84, but the current outbreak is already far more widespread, according to the limited data available. That outbreak decimated the area’s starfish and occurred during warmer waters of an El Niño phenomenon. Scientists believe the warmer temperatures allow the syndrome-causing bacteria to proliferate.
However, marine temperatures off Bodega Bay have been below average this year and near- average throughout the northeast Pacific, John Largier an oceanographer at the Bodega Marine Lab told The Press Democrat.
Raimondi said this fact “makes this event unusual and perhaps more disturbing.”