Thursday, January 18, 2007
Invasive species at Lake Ontario
SYRACUSE, N.Y. - Another invasive species, a half-inch long ravenous shrimp from Eurasia, has been found in Lake Ontario, raising concerns among scientists that the tiny crustacean could mean dire consequences for the lake's food chain. The discovery of bloody red mysid — whose scientific name is Hemimysis anomala — was made in a lake sample taken near Oswego last spring, said Chuck O'Neill, Jr., an invasive species specialist with New York Sea Grant and a member of New York State's Invasive Species Task Force, on Wednesday.Its only other confirmed appearance in the Great Lakes region was last November in a channel of Muskegon Lake, which empties into Lake Michigan.The red mysid is closely related to the possum shrimp that live in the Great Lakes. It is native to the Caspian Sea and Black Sea areas of Eurasia — the same region that sent zebra mussels, quagga mussels and gobies, other invasive species, to the Great Lakes. Like most non-native species in the Great Lakes, the red mysid is presumed to have arrived in the ballast of oceangoing ships.The shrimp has already been documented in parts of Europe. The red mysid has "strong potential" to severely affect the lake's food chain, O'Neill said.Typically, the shrimp feast on phytoplankton and zooplankton, the foundation of the lake's food chain. Zooplankton are also what many young fish thrive on."Hemimysis is an opportunistic predator. They will eat whatever is available, which means they will be infringing on the food sources for other species," O'Neill said. So far, scientists have found red mysid only off Nine Mile Point in eastern Lake Ontario, but they are likely more widespread."The Lake Ontario discovery included both juvenile and adult Hemimysis, suggesting that the population has had time to establish itself and reproduce in Lake Ontario," O'Neill said.David MacNeill, a fisheries specialist with New York Sea Grant, said Lake Ontario offers a friendly habitat for the red mysid, which prefers warm, shallow waters with rocky bottoms and likes to swim near the shore and near piers."It's hard to make predictions," said MacNeill, noting that there are a number of species of fish that will eat the red mysid, which could balance some of their negative influence."But whenever you introduce a non-native species, it is a game of environmental Russian roulette. Something bad is likely to happen, the question is just how bad that something will be," MacNeill said.Scientists, meanwhile, are asking the public's help to catalog the extent of the red mysid invasion. A fact sheet is being prepared to help shoreline residents and Great Lakes users spot Hemimysis, often seen as a large reddish swarm in the water, said David Reid, director of the National Oceanic and Atmospheric Administration's National Center for Research on Aquatic Invasive Species. Research technicians will collect samples for confirmation.Exotic species documented in the Great Lakes now number at least 185, with new invaders discovered at a rate of one every eight months, according to the Great Lakes Environmental Research Laboratory in Ann Arbor, Mich.