LAKE GEORGE — Invasive Asian clams continued to spread in Lake George over the past year, colonizing at least one new site, according to a report released Wednesday.
An annual survey conducted by Lake George Park Commission last week identified “a very large site” in the Hague Brook delta around the hamlet of Hague at the north end of the lake. The 2017 survey found four new sites.
“It was good news that we found only one site. Unfortunately, it’s the largest sandy site in Lake George,” said David Wick, executive director of the Park Commission. “It wasn’t unexpected.”
The identification of the site, which may cover as many as 20 acres, means there are now about 120 acres of shallow sandy bottom infiltrated by the tiny clams across 24 locations. At this point, trying to eliminate the invader would be “cost-prohibitive,” the commission’s report states.
The majority of sites are in the more-popular southern basin of the 32-mile-long Adirondack lake.
The infested beds are almost entirely in sandy, shallow waters, including at the state-owned Million Dollar Beach at the southern tip of the lake. Million Dollar Beach currently has the highest clam density identified this year, at an average of 20 clams per sieve.
The clams can spread from location to location by water current, but researchers also believe that they can be transported by boat anchors pulled up from the bottom. “We encourage people to wash their anchors,” Wick said.
The recent survey was conducted over four days from Aug. 20-24, with more than 20 people — many of them volunteers — using sieves to comb through the sandy shallows that provide the dime-size clams’ preferred habitat.
Wick acknowledged the commission has largely given up on active efforts to eradicate Asian clams because of the enormous cost. Using benthic barriers — mats spread over the bottom of the lake to suffocate the clams — costs $60,000 to $80,000 per acre. The problem is that if even a smaller number of clams remain after the treatment, they repopulate quickly.
The last effort to eradicate a clam bed, at the Rogers Rock Campground in 2015, cost more than $100,000. While the site remained clam-free in 2016, last year’s survey found that the clams had returned.
Asian clams were first discovered in Lake George in 2010 and have continued to spread year-by-year, despite several years of aggressive efforts to eradicate them. Left unchecked, Asian clams can reproduce exponentially and cause negative ecological and recreational impacts.
“At this time, there have not been significant recreational or environmental impacts from this species in Lake George, although populations have been expanding throughout the lake, and the future remains unclear,” the report states.
“The good news is that nobody from the general public would really know they were there, but our concern is long-term,” Wick said.
While cold winters have killed a large number of clams in some years, Wick said there’s a concern that clams that can survive in frigid water will pass that trait on to offspring, with more clams surviving harsh water conditions in the future.
Wick said the long-term risk is that winter-hearty clams could proliferate, leaving thousands of shells on beach bottoms, discharging nitrogen into the water and raising the risk of algae blooms in the lake, which is famed for its water quality.
Separately, state and local officials are working on plans to reduce the discharge of algae-promoting nutrients into the lake from wastewater treatment plants, stormwater runoff from developed areas and other sources.