Sea stars wasting away on both U.S. coasts
Evidence suggests that we are at the onset of another sea star wasting event. Sea stars on both the east and west coasts of the United States have fallen victim to a wasting disease that overcomes the Pisaster ochraceus in a matter of days once an initial lesion appears. The disease, while currently not understood, is rapidly transmitted amongst the population once it takes hold. On the west coast studies show that the disease is bacterial but on the east coast it is viral. Both result in a similar disintegration of the flesh within a very short period of time.
Sea Star Wasting Syndrome has been documented for the last three decades by research teams from the University of California, Santa Cruz Pacific Rocky Intertidal Monitoring Program. Scientists have suspected warmer than normal temperatures associated with climate change to be a potential cause. Wasting events have been documented in the past, in particular, one event dating back to 1983-84 in Southern California and a second, albeit smaller event, between 1997-98. West coast monitoring has been done at more than 200 sites from Southeast Alaska to Mexico. Additional studies have been done on the east coast off the coast of Maine.
Rocky intertidal habitats occur on the shores at the interface between the terrestrial and marine environments. This unique location results in a physical complexity that leads to high biological diversity, including many species that are found only in this narrow band of coastal environment. Rocky shores are also the most accessible marine habitat, which fosters a strong public appreciation of these communities, but also makes them vulnerable to degradation resulting from human activities. Natural temporal variation in rocky intertidal systems can be quite high, and can occur on the scale of months (seasonal), years, and even decades, so long-term monitoring is essential for separating natural change from human-induced.
The brightly colored Pisaster ochraceus sea star subsists on barnacles, snails, limpets and chitons and can live for up to 20 years. Population recovery after a wasting event is apparently due to cooler-water conditions and large recruitment events, which have been documented in many, but not all areas. The wasting events have been recorded as far north as British Columbia. The ongoing monitoring project includes an interactive map documenting the location and severity of the outbreaks.
Read more at the University of California, Santa Cruz.
Pisaster ochraceus image via Shutterstock.