|Sea star disease in Port Orford|
|Written by Jane Stebbins, Pilot staff writer|
|July 08, 2014 07:19 pm|
The sea star wasting disease has crept into Port Orford — and the demise of the colorful creature could spell the collapse of the entire ecological system in which they live.
The disease is spreading quickly.
According to evaluations conducted by the Partnership for Interdisciplinary Studies of Coastal Oceans (PISCO) collaborative, scientists found 1,000 sea stars at Fogerty Creek near Newport at the beginning of May. Of those, seven showed signs of the wasting disease.
Two weeks later, 34 out of 1,400 tested positive, and by May 27 researchers only found 488 starfish, and 235 of them had signs of the disease.
On June 29, it struck the purple ochre starfish at Cape Blanco north of Port Orford.
“There have been changes in the Port Orford area,” said Angela Johnson, faculty research assistant with PISCO, “and not for the better.”
The disease is affecting both orange and purple sea stars that in the ocean have a population ratio of 3:1, purple:orange.
The percentage of sick orange stars is much higher than the percentage of purple stars, Johnson said, and juveniles are faring better than the adults.
“We have no idea why,” she said, “but it is interesting, to say the least.”
The syndrome was first noticed along the west coast of Canada shortly after the earthquake and subsequent tsunami in Fukushima, Japan. Some people speculated that radiation was causing the sea stars to self-destruct, but that was soon proven not to be the case.
Scientists still aren’t sure what causes the starfish to sluff off its arms and dissolve, and are researching to see if it’s bacterial, viral, due to climate change or ocean acidification, which is occurring as the ocean absorbs the world’s carbon.
Initially, warmer water seemed to be the primary culprit, but now it is reported that water in Oregon is at normal levels, and the sea stars are still dying in droves.
“The verdict is still out on what is causing it,” Johnson said. “There are several people running experiments to try and pinpoint the culprit, but it is a tedious process. It seems that it is probably a multi-faceted issue.”
The wasting disease first hit the purple ochre stars, and has now spread to 20 species, including a large sunflower star that can get as big as the lid of a trash can.
The dying starfish were then found in California, then Washington coasts. It was just a matter of time until they’d be seen in Oregon — in April, when one was found in Yaquina Bay in Newport.
That prompted scientists to flock to coastal tide pools in droves, to both count sea star populations and determine the rate at which they were dying.
It wasn’t pretty.
Locally, Cape Blanco’s sick population went from .25 percent on May 17 to 41 percent June 15 — an increase of some 16,000 percent.
The sick sea stars at Port Orford Heads represented .55 percent of the population on May 18 to 18.7 percent on June 16.
And Rocky Point stars went from .63 percent sick on May 18 to 31.6 percent sick on June 17.
The starfish at Port Orford Heads and Rocky Point did not have advanced cases of the illness, and while researchers have determined it is usually fatal, sometimes afflicted sea stars survive.
The descriptions including “gooey,” “dripping,” “disintegrating,” and “melting.”
The stench is unbearable in some spots, as they rot away.
Farther south, at Pyramid Point, mid-June reports indicated that wasting disease is present at a “high” rate, PISCO’s worst rating.
Scientists report that affected sea stars typically first contort and twist, and white lesions appear on their bodies. Their bodies deflate and waste away, arms detach — and walk off on their own, disintegrating as they move.
The sea stars can no longer stay attached to rocks, and fall. The animal loses its ability to hold on to rocks or pilings. Its body falls apart in pieces, and finally dissolves. Within weeks, only a ghostly white print will remain, and then nothing at all.
The starfish are the equivalent of the canary in the coal mine: when they die, it’s an indicator that something is wrong. Such “keystone species” die-offs can often result in a complete shift in the local ecology, as is being witnessed off Vancouver Island.
Green sea urchins, it was reported last week, have exploded in numbers there and are devouring seaweed that spot prawns need in their first year of life.
“It’s bigger than the die-off,” Jeffrey Marliave, vice president of marine science at the Vancouver Aquarium, was reported as saying last week. “It’s affecting the whole ecosystem.”
Johnson said it’s too soon to use the word “extinct,” as sea stars are broadcast spawners that don’t depend on finding one another to mate.
“At this point, it seems there are enough sea stars remaining that bringing the population back to the numbers we were seeing in the winter is quite feasible,” Johnson said.
But the intertidal zone could, with a decrease in starfish, be overwhelmed with mussels, and algae beds could become overgrown, she said.
“As far as my thoughts, I could go on forever,” she said. “It’s sad to see the most charismatic species of the intertidal (zone) suffering, and scary to not know what is causing it or how to fix it.”