Destructive Zebra Mussels Invade Another Connecticut Lake

STORRS — Zebra mussels, an invasive species responsible for billions of dollars of economic and ecological damage in the Great Lakes, is spreading among Connecticut’s lakes and may be headed for the Housatonic River.

The freshwater mollusks were first discovered in East Twin Lake in Salisbury three years ago. Dive surveys by the Connecticut Department of Environmental Protection in 1999 and 2000 showed the number of mussels increasing in East Twin Lake, but no evidence of them in West Twin lake.

On August 20, Nancy Balcom, an extension educator with the Connecticut Sea Grant College Program at the University of Connecticut, and James Carlton, an invasion ecologist at Williams College, surveyed West Twin Lake and found abundant evidence of the mussels.

“Our discovery indicates that zebra mussels have now clearly established a major beachhead in Connecticut, and it is imperative that boaters and fishermen become aware of these infestations and take action to avoid spreading the invaders,” Mr Carlton said.

Zebra mussels are native to Eurasia and are prolific reproducers. They grow to about one inch in size, can produce 30,000 eggs in one season, and readily attach to any hard surface, creating huge colonies. They  can clog intake pipes of factories, water and sewage treatment facilities. They foul boat hulls and engines. They destroy marine life by filtering plankton from the water, thereby removing the primary source of food for some fish species and other organisms.

Carlton and Balcom fear that the Housatonic River will be infested eventually, because it is connected to West Twin Lake by Schenob Brook. This is particularly troubling because several hydroelectric plants are located along the Housatonic and three lakes are fed by the river, including Lake Lillinonah, Lake Zoar, and Candlewood Lake.

Ms Balcom, whose expertise is non-indigenous nuisance species, says the zebra mussel larva is microscopic, floats on water, and easily spreads without being detected. Several weeks later, the mussels attach themselves to aquatic weeds and other hard surfaces.

“It is imperative that all boaters and anglers who spend time on the Twin Lakes, or any lake for that matter, take time to clean weeds from propellers, ropes, trailers, and fishing gear to avoid transporting the invaders to another body of water. Just a fragment introduced to another lake can lead to new invasions,” she explained. This warning also goes for personal watercraft.

Ms Balcom says surveys will be conducted in a couple of weeks to determine if the destructive invaders have reached Schenob Brook.

The initial discovery of zebra mussels in Connecticut came in the summer of 1998 by Charles Ouellette, a Salisbury town employee responsible for mechanically harvesting an invasive aquatic weed called milfoil from the town’s lakes. The mussels were attached to the milfoil.