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Tuesday, February 06, 2007

Grim News For Great Lakes: 183rd Invasive Species Found

CLEVELAND (TDB) -- A small shrimp with a big appetite for microscopic animals at the bottom of the freshwater food chain has colonized the Great Lakes. Large concentrations of the invaders were found in November and January. Scientists say the shrimp, Hemimysis anomala, is native to rivers in Eastern Europe, the same region where zebra mussels originated. The shrimp is the 183rd species to invade the lakes, and there are concerns it could disrupt the food supply that fish depend on for survival.

Others think that native fish might find the recently spotted newcomers a tasty crustacean on the menu. But for now, most scientists seem to be in the bad news camp. In the past, zebra mussels, quagga mussels, gobi and lamprey eels -- among the many prior invaders -- usually produce ill effects on the natural environment.

Nobody is sure how the so-called "bloody red" shrimp entered the lakes, but researchers suspect they came in ships' ballast waters. The crustaceans are about a half-inch long, they live near shoreline waters, and females were breeding in Lake Michigan in November. The National Oceanographic and Atmospheric Administration received a report in mid-January that another concentration had been found in southeastern Lake Ontario.

Photos of the shrimp are HERE on the Web site of NOAA's Great Lakes environmental research lab in Ann Arbor, Mich. A map HERE shows where the concentrations have been located and gives some details about the sightings.

NOAA has a fact sheet about the bloody reds HERE that offers information about their life-style habits and recent intrusion. The shrimp's appearance in the lakes raises questions about how effective ballast-water dumping regs are working. Transatlantic cargo ships are expected to dump ballast water from foreign sources before entering the lakes. But some does get through and harbors alien stowaways.

Researchers at McGill University in Canada have projected that the Great Lakes are extremely vulnerable to 17 species from Eastern Europe. This is the first on the list to show up.

The Great Lakes are home to a small North American shrimp called mysid. They won't be competing directly with the new shoreline hugging arrivals because they live in deeper, cooler waters. So far, the invaders have not been found in Lake Erie. But that could change rapidly.

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