|Wasted starfish (PHOTO: Nate Fletcher)|
The mass die-off has received ample media coverage from last fall through this winter. [See: Mysterious epidemic devastates starfish population off the Pacific Coast and Northwest Starfish Experiments Give Scientists Clues To Mysterious Mass Die-offs]
The mass die-offs of certain species like sunflower, mottled and ocher starfish which develop lesions and rapidly disintegrate had been first reported last summer on the Olympic coast, followed by reports from hardest hit areas like Seattle, Vancouver BC, Monterey, Santa Barbara and Long Beach CA. As observed, adult starfish, according to Ben Miner, prove much more susceptible than juveniles. The rate of die-offs slowed from the fall into the winter. In Puget Sound, the disease has moved through starfish populations from Seattle north to Mukilteo and to Langley and Keystone on Whidbey Island.
What is and isn’t known at this time:
Experiments demonstrate that the cause is a pathogen transmitted from infected starfish to healthy ones and not an environmental toxin or parasite which would affect other starfish species and other marine life. The pathogen is water borne and affects starfish in aquariums and marine laboratories; starfish in filtered aquarium water show no signs of infection.
The pathogen may be bacterial or viral, like the parvo virus which causes tissue degeneration but experiments have not proven definitive. Shooting up an infected starfish with antibiotic stops the infection but the starfish dies when the treatment stops. All starfish don’t get infected and die, which may mean that some starfish have an immune capability or a combination of environmental factors are at play that result in infection and death. (Shooting up a Crown of Thorns starfish with bacteria in an unrelated experiment showed a fatal effect resembling wasting disease.)
“If it were straightforward, you’d have got it already,” Miner said. Like bee disease and colony collapse, there may be multiple factors that increase organism stress and suppress immune systems. What makes the starfish sick may be gone by the time it dies. If there remains uninfected areas where healthy and unhealthy starfish can be studied, there’s a chance the mystery might be solved. If wasting disease spreads everywhere, there won’t be anything left to study.
One consequence of the mass die-off is changes in ecological balance in certain areas. The starfish around marine reserves have traditionally feasted on lingcod eggs. With the absence of starfish predators, lingcod are expected to thrive. The effect of increased predation by lingcod on other species will be interesting to see.
The environmental factors associated with wasting disease may be related to conditions found in populated and protected areas where die-offs have been highest. The die-offs have slowed during the winter, indicating a possible correlation with climate and water temperature. Likewise, the reports from past die-off episodes in California and Baja waters have been associated with El Nino years and warmer waters in the late ‘70s, early and late ‘80s, and the ‘90s. Alas, NOAA predicts an El Nino year for 2014-15 and, as Eric Holthaus in Slate sees it, “Seattle: A warm winter, and especially warm waters offshore, could be tough for the Pacific Northwest salmon.” [What Does El Niño Mean for Me?]
Might be worse for our starfish. As the spring and summer arrive, watch carefully.
[Oh, regarding radioactivity from Fukushima to blame, not. The timing is wrong, only some species of starfish are wasting, and there are no other marine critters showing radioactivity effects.]
For complete up-to-date reports and maps and images of the disease, go to the UC Santa Cruz wasting site.