Invasive brittle star species hits Atlantic Ocean

Coral Reefs, the Journal of the International Society for Reef Studies, has published online a study co-written by Dr. Gordon Hendler of the Natural History Museum of Los Angeles County (NHM) about an invasive species of brittle star, Ophiothela mirabilis. The species was previously restricted to Pacific waters, but surprisingly, growing populations have established themselves at distant points in the Atlantic. Its presence near Brazilian and Caribbean ports indicates that O. mirabilis could have been spread by shipping. The marine animal is colorful and six-rayed. It clings in multitudes to corals and sponges and reproduces asexually, by splitting in two and regenerating severed body structures. The ability of one star to "clone" vast numbers of identical twins enormously increases the species capacity to proliferate and disperse.

The impact of the ophiothela brittle star remains to be seen. Like most marine invertebrates (except for commercially important species) we know little about its biology, so it is difficult to envision how it will affect the ecology of its new ocean. But further expansion of the range of Ophiothela could alter the appearance and the ecology of Atlantic coral reef habitats because ophiothelas, in multitudes, densely colonize gorgonians and sponges on Indo-West central Pacific and on tropical eastern Pacific reefs.

"I imagine that when my grandchildren learn to scuba dive," Hendler says, "Caribbean reefs will look very different than they do today, in part because many corals and sponges may be covered with a network of invasive yellow brittle stars."

Invasive species have a massive impact on our economy and our environment, causing over 100 billion dollars of damage in the U.S. alone, every year. Invasive echinoderm species are exceptional (invasive plants and insects are much more numerous). Probably the best known is the Japanese sea star (Asterias amurensis) that was native to the north Pacific and now damages fisheries in Tasmania and southern Australia. Notably, it is among the species that recently washed ashore in Oregon on Japanese Tsunami debris.

Source: Natural History Museum of Los Angeles County