Losing Constellations of Sea Stars

                In most environments that starfish are involved in they happen to be a keystone species, which is a species that the food web there is dependent on, without that species prey would explode and their predators were struggle to find a new means of food source; only a few are needed to make a weighty impression and alteration to the ecosystem. Throughout the west coast of North America this keystone species has been dying at a startling rate. A tragic and brutal seeming disease has killed millions of these creatures from Alaska down to California just since the beginning of June 2013. This disease causes the starfish’s legs to fall off and their internal organs to spill out into the ocean, this is occurring with both wild and captive starfish. The director of the US Geological Survey’s National Wildlife Health Center, Jonathan Sleeman, has tentatively named this disease “Starfish Wasting Syndrome”.

                Starfish emerged at approximately the same time frame that sharks did, 450 million years ago. Since then 1500 different species of echinoderms have been identified, but only two of which have been predominately affected by this lethal disease: the purple sea star (Pisaster ochraceus) and the sunflower sea star (Pycnopodia helianthoides). These species are some of the many that can regenerate their arms if they happen to become detached, but once infected with this disease it is not possible because death occurs so quickly. Immediately after a starfish is infected, its arms will break out in white lesions which will spread and result the arms to deform and lead to them falling off, due to the limbs breaking off, the body of the starfish loses its integrity and releases its internal organs, which this the ultimate end to the organism. Once signs of the infection occur, there is a 95% chance that the echinoderm will die, and that will occur in the following few days.

                A small population was infected on the east coast but never managed to spread along the coastline, miraculously. This disease is baffling and beating biologist across the board, whom are sampling and analyzing the two species to determine the cause, but so far to no avail. The current hypothesis rests on pollutants or an infection; an infection from a microorganism such as a virus or parasite is what they are currently leaning towards, but are yet to have any solid backing.

                                Starfish are similar to coral, in that they are highly sensitive and susceptible to changes in the water temperature and climate fluctuations, but for starfish that only tends to kill small populations. Warming waters has never produced deaths on this scale before; prior die-offs had easily identifiable causes and affected a fraction of the number of starfish that were lost last summer.  Without these keystone species both warm and cold water ecosystems are prone to suffer and potentially collapse, as will our various fishing industries that are dependent on them.

http://www.nwhc.usgs.gov/publications/wildlife_health_bulletins/WHB_2013-06_Sea_Stars.pdf

Nicole Peterkin (6)