The largest reservoir in Connecticut and one of its most popular bass fisheries is at risk of infestation by zebra mussels.
"They're not on in Candlewood yet, but they're right on our doorstep," said Len Greene of FirstLight Power Resources, which owns and manages the lake and a hydro power station on it. "It was only a matter of time before they migrated there."
"There" is the station's foundation on the Housatonic River and nearby boulders. In 2009, the invasive mussels were found in nearby Lakes Lillinonah and Zoar and in the river itself.
And the threat lies in way that power is generated, by pumping water between the lake and the river. In the past, FirstLight has voluntarily limited pumping during times when mussels reproduce to lessen the threat, and plans to continue doing so.
"We've been able to buy five years with the pumping restrictions," Greene added. "It's an unfortunate situation that I think was inevitable at some point, given that zebra mussels spread everywhere they can."
As officials try to decide on the best way to repel a zebra mussel invasion, Candlewood Lake Authority has suggested a smaller than normal winter drawdown to reduce the risk when the lake refills with river water. Typically, water is drawn down 6 1/2 feet to knock back another invasive, Eurasian watermilfoil. Executive Director Larry Marsicano added that the authority can monitor the area around the intake pipe.
"We're still trying to manage the risk of them getting a toehold," he said. "Even if one gets pumped in, it takes two to tango."
Aside from the threat that they post for blocking water intakes with their dense colonies, zebra mussels also improve water clarity as they feed on algae and plankton. That would allow for more light penetration, encouraging already problematic watermilfoil to grow faster and spread into deeper water.