Skin discolored and ulcerated, arms crippled and lifeless, intestines spilled out—since 2013, starfish around the world have been stricken with a mysterious disease. Biologists from Queen’s University in Belfast have now also discovered the first cases of this »Sea Star Wasting Disease« (SSWD) in European waters. Several specimens of the Common Sunstar caught off the east coast of Ireland (Crossaster papposus) died after a short time in the seawater aquariums of the research institute, they report in the “Biology Letters” of the Royal Society.
For their study, Samuel Smith’s team collected around a dozen specimens of the common sun star from crab baskets in the Irish Sea and initially brought them to the laboratory for behavioral studies. But the animals soon showed the first typical signs of the disease: “After five days, the starfish, which initially appeared healthy, showed the first symptoms of the sea star wasting disease,” the researchers report in their article. The sun stars developed white spots, their bodies writhed and became abnormally limp. In the days that followed, the symptoms worsened, until eventually two-thirds of the starfish were dead.
The findings showed “that native starfish species in Europe are also susceptible to SSWD,” the researchers write. They therefore fear that the phenomenon is already much more widespread in European waters than previously thought and that previous mass extinctions can already be attributed to SSWD.
Starfish are important predators in their ecosystems
According to the scientists, if the disease spreads further, this could have far-reaching ecological consequences: “Many starfish are very important predators in their ecosystems, which, among other things, regulate the composition of the invertebrate fauna on the sea floor,” they explain. For example, the common sun star is an important predator for other echinoderms, including the common starfish Asterias rubens. If the sun star is missing, mass reproduction of other species can result.