Starfish wasting disease or sea star wasting syndrome is a disease of starfish that appears sporadically, causing mass mortality of affected starfish. The disease is little understood and no identifiable cause for these events has been found, although it seems to be associated with raised water temperatures. It starts with the emergence of lesions, followed by body fragmentation and death. The cause of the syndrome is unknown.
A die-off of large numbers of common starfish (Asterias rubens) occurred in 1972 off the east coast of the United States. The starfish became limp and fell apart into pieces.
In 1978 large numbers of the predatory starfish Heliaster kubiniji succumbed to a wasting disease in the Gulf of California. At the time it was suspected that high water temperatures were a causal factor. This starfish became locally extinct in some parts of the gulf and some populations had still not recovered by the year 2000. Because this starfish is a top-level predator, its disappearance had profound effects on the ecosystem. In the Channel Islands off the coast of California, ten species of starfish were recorded as being affected as well as three species of sea urchins, two brittle stars and a sea cucumber, all of which experienced large population declines.
In July 2013, populations of starfish declined rapidly on the east coast of the United States between New Jersey and Maine. There had been a great increase in starfish numbers three years earlier and now they were dying off. No cause for the mysterious deaths was apparent.
At the beginning of September 2013, a mass die-off of starfish was reported off the coast of British Columbia. The sea bed was littered with disintegrating sunflower stars (Pycnopodia helianthoides), their detached arms and discs. Another species also suffering mortalities was the morning sun star (Solaster dawsoni) but no cause for the deaths was apparent. If they were caused by infection or toxins, the two species might have affected each other because the diet of each includes starfish
In October 2013, in a marine laboratory seawater tank in California holding various species of starfish, other species started displaying similar symptoms. The ochre star (Pisaster ochraceus) was the first affected. Most of these developed symptoms, lost arms and died over the course of a week or so. Later the rainbow star (Orthasterias koehleri) developed the disease and died, but the bat star (Patiria miniata) and leather star (Dermasterias imbricata), which were living in the same tank and had been scavenging on the corpses, showed no ill effects. At Natural Bridges State Marine Reserve in California, the ochre star is normally a very common resident on the mussel beds, but in November 2013 it was reported to have completely disappeared.
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