Threat to Lake George in clam species

Officials are hoping a rapid response can contain a new invasive species, the freshwater Asian clam,

Categories: Schenectady County

Officials are hoping a rapid response can contain a new invasive species, the freshwater Asian clam, in the southern part of Lake George.

The species was found last week in waters just off the village of Lake George, the lake’s most popular swimming and boating area, by a student at the Darrin Fresh Water Institute in Bolton Landing.

It’s a clam that has damaged water quality in Lake Tahoe, in one of its most notable outbreaks. It has the potential to spread rapidly and promote algae blooms in Lake George’s clear water, officials said.

The infestation is believed to cover at least 2.5 acres of lake bottom, and divers are now checking for more. Dives on Thursday and Friday found no further spread, though the one identified area likely contains thousands of clams.

“It is imperative that we move quickly to determine the extent of this infestation and assess the best treatment options that can be undertaken immediately,” said Sandra Nierzwicki-Bauer, director of the Darrin Institute, which is part of Rensselaer Polytechnic Institute.

Possible eradication or management strategies include using a benthic barrier, a kind of plastic mat that could cover the clams, suction harvesting, or a combination of the two methods. The Adirondack Park Agency and the Department of Environmental Conservation’s Office of Invasive Species Coordination will be involved in the response. Any solution is likely to require a DEC permit.

Divers were already helping with control of another invasive species in the lake, Eurasian milfoil, and were able to respond quickly to the Asian clam find.

“We don’t know the current extent of the Asian clam infestation, but if we’re lucky maybe this is an isolated infestation in Lake George that we caught early,” said Peter Bauer, executive director of the Fund for Lake George, which is paying for the dive survey.

Lake George has seen the appearance in recent years of several other invasives as well, including curlyleaf pond weed and zebra mussels.

Between the Fund for Lake George, the Lake George Park Commission and the Lake George Association, Bauer estimated nearly $300,000 a year is spent on controlling invasive species in Lake George.

The Lake George Association, a residents’ group, will be distributing educational materials so people can identify the Asian clam, and so that boaters don’t further spread the problem. The association is also emphasizing that people clean their boats and drain all bilge and bait water when taking their boats from the lake, especially in the heavily trafficked Southern Basin.

The clams probably were brought to Lake George in bilge or bait water, said Emily DeBolt, director of education for the Lake George Association.

“We don’t know how long they’ve been in the lake,” DeBolt said. “We’ve found both small and larger sizes, which indicates they’ve more than likely reproduced already. But we don’t know if it was last year, or the year before.”

Asian clams, or Corbicula fluminea, are native to Southeast Asia and were first documented in the United States in 1938. Since then, they have been found in 40 states.

The clam has been found elsewhere in New York, including the Champlain Canal at Fort Edward, but this is the farthest north an established colony has been found.

The clams have an oval triangular shape, with a shell that ranges in color from yellow-brown to black, and concentric ridges on the outer shell. The clams are self-fertilizing and capable of rapid reproduction under the right circumstances, though for many years the Northeast was thought to be too cold for them.

They have been found in the Hudson River for a number of years.

Geoffrey Schladow of the University of California, Davis, who has worked on the 8-year-old outbreak in Lake Tahoe, said the clams excrete nutrients that can promote the growth of algae.

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