A disease affecting over a dozen starfish species is decimating coastal populations from Alaska to Mexico. Called Sea Star Wasting Syndrome, the pathogen, possibly Densovirus, is infecting starfish, causing the limbs to detach and their bodies to melt, with some infected individuals dying within hours. Billions of starfish are thought to have died from the disease to date, causing a knock-on effect in the ocean ecosystems they inhabit. The disease has been so severe that the Washington Post is claiming that its the “largest known outbreak of disease among marine animals to date,” which when you put it into context, is a very scary prospect indeed.
One affected species is the Sunflower Sea Star, Pycnopodia helianthoides, a three-foot wide predatory starfish that preys on clams, snails, and sea urchins. Over five billion Sunflower Sea Stars are thought to have died since 2013, allowing urchin numbers to boom and their food source, kelp to decline by up to 95% over the last ten years in Northern California. Kelp sequesters large amounts of carbon dioxide from the atmosphere which is critical in the fight against climate change. In a snowball effect, the warming of the oceans and spikes in sea temperatures are thought to be the critical stressor of the affected starfish as well as an increase in nutrients. With the urchins running riot and decimating kelp forests, CO2 increases, water further warms, and the whole thing worsens for all the other animals that depend on kelp forests for their survival.
Some of the public aquariums on the West coast have also been infected by the killer disease, introducing it via the seawater they pump into their displays. These institutions are also helping find a cure, however, with the Oregon Coast Aquarium reportedly saving 15 out of 17 infected animals with protocols including iodine baths and probiotics. The US government has placed the Sunflower Sea Star under the Endangered Species Act. The University of Washington is working to initiate captive breeding.