Graduate student Beth Shedden and Professor John Kelly examine specimens at Long Wharf pier. (Photo:UNH)
Invasive sea squirt puts Connecticut's shellfish sector on alert
Thursday, September 29, 2011, 15:20 (GMT + 9)
The invasive sea squirt Styela clava has appeared along the Eastern Seaboard and is threatening Connecticut’s USD 30 million shellfish business, informed Carmela Cuomo, head of the marine biology programme at the University of New Haven (UNH).
The migration of the foreign pest southward from Canada and northern New England jeopardizes the farming of bivalves such as clams, mussels, scallops and oysters in Long Island Sound.
Connecticut’s shellfish industry provides 300 jobs and has 70,000 ac of shellfish farms, according to the Connecticut Department of Agriculture.
“The spread of this particular species of sea squirt westward in Long Island Sound, along with laboratory studies of its temperature tolerance, indicates it can survive at higher water temperatures than scientists had previously believed,” Cuomo said. “If further testing confirms that Styela can reproduce in warmer waters, Styela may pose a greater threat than has previously been imagined and may even be able to spread as far south as Florida.”
|Professor Carmela Cuomo discusses the potential impact of Styela clava on Long Island Sound. (Photo: UNH)
Similar to other sea squirts, Styela eats plankton by filtering seawater through a bronchial sac inside its body cavity. It pumps and expels the water screened for food.
Cuomo and two undergraduate researchers in UNH’s marine biology programme, Kathleen Sandin and Nicholas Brunetti, have spent the past two months tracking Styela clava along the northern coast of Long Island Sound. They found that Styela has travelled as far west as Bridgeport, Connecticut, approaching the oyster farms in the Sound near Norwalk, Connecticut.
The team continues to track the path of the species southward and to study its environmental tolerance.
“The invertebrate does not appear to have any natural predators in the region, and any agent that might be introduced to kill the organisms en masse—such as concentrated salt or lime—could also damage the species Connecticut has worked so hard to protect,” Cuomo detailed.
The most reliable method to eradicate Styela is to scrape specimens off surfaces to which they are stuck, such as the hull of a ship.
Another problem facing Connecticut now is an invasive species of shrimp, stated John Kelly, assistant professor of marine biology at UNH, and graduate student Beth Shedden.
|Palaemon macrodactylus. (Photo: UNH)
Oriental shrimp (Palaemon macrodactylus) like Styela, come from the waters off Korea, Japan and China. They were first seen on the east coast of the US in 2001 near New York City.
Kelly and Shedden have gathered samples of oriental shrimp from across Connecticut, including within the New Haven Harbour. They are trying to resolve how well-established the shrimp is locally, what habitats it prefers and whether it is a threat to native species.
By Natalia Real