By Malee Oot May 12, 2014
Above: photo gallery of wasting disease, from Jonathan Martin via Flickr.
Starfish along the Pacific coast have been dying in considerable numbers since last June, and marine scientists are still struggling to pinpoint the specific reason. The scale of the die-off the staggering; starfish wasting events in the past have been observed with a single species, but in this case, the die-off has been documented along the entire length of the Pacific coast, and is affecting a number of species, according to regular field observations from the Multi-Agency Rocky Intertidal Network (MARINe), a consortium of cooperating marine research groups. And as the mysteriously die-off continues, some scientists are questioning a link to global climate change.
Also known as sea stars, starfish are actually echinoderms, and are considered a keystone species, that is, vital members of the ecological communities in which they exist. In fact, the term ‘keystone species’ was coined by University of Washington ecologist Robert Paine after a studies assessing the role of sea stars in intertidal ecosystems in the Pacific Northwest.
Starfish are also good indicators of the overall health of the ecosystems in which they live—if starfish are dying, many times, it is an indication of a larger ecological disturbance of some kind.
The mysterious disease afflicting Pacific starfish in droves has been termed ‘sea star wasting disease,’ and observers have reported that the invertebrates seeming to disintegrate, losing limbs and body structure.
The disease appears especially virulent as starfish are known for being able to regenerate their bodies after trauma, even able to regrow a full body from just one part of a remaining limb.
Researchers along the Pacific coast have even asked the public to share and document their observations of the disease at www.seastarwasting.org.
Scientists believe the cause of the widespread wasting is something infections—a bacterial or viral pathogen of some type. Anecdotal reports from the New England suggest the outbreak is occurring there as well.
However, a climate change connection has not been ruled out. The last three major sea star wasting events in southern California (during the late 1970s, 1983-1984, and 1997-1998) have all been associated with warmer water events, according to MARINe.
This time, it is not likely that warmer water temperatures are causing the die-off. Pete Raimondi, Chair of the Department of Ecology and Evolutionary Biology at the University of California Santa Cruz explained to NPR station KQED, ‘Although climate change is warming the ocean overall, the ocean along the West Coast has been in a cool period since the 1997-1998 El Nino.’ But, Raimondi continued to suggest, a climate connection, like shifting ocean currents could still be contributing to the die-off.
Other scientists have also suggested climate change could be exacerbating the sea star wasting phenomenon. University of Western Washington professor of Marine Biology Benjamin Miner, said during the same interview that effects from climate change could be suppressing sea stars' immune systems and making them more susceptible to lethal pathogens.