Lake Protection Groups Mount Rapid Response Effort to Contain Spread of Asian Clam

BY ANTHONY F. HALL

Just when scientists from the Darrin Fresh Water Institute were starting to feel confident that an invasion of Zebra mussels had been successfully repulsed, they discovered that another non-native mollusk has begun colonizing Lake George: the Asian clam.  “It was a horrible day for Lake George, but given our success with combatting Zebra mussels, we’re hopeful that the Asian clam has been identified early enough that we can eradicate it,” said Sandra Nierzwicki-Bauer, the executive director of DFWI.  “We won’t know for sure until we’ve  investigated further.” According to Nierzwicki-Bauer, Jeremy Farrell, a Fresh Water Institute research scientist, discovered a clam near Lake George Village’s Lake Avenue last week that he was unable to recognize. It was identified by Nierzwicki-Bauer and Dr. Dan Marelli, an expert on clams and mussels who is a visiting researcher at DFWI, as an Asian clam.

The Asian clam was in all likelihood introduced by fishermen, who use the clam as bait, said Nierzwicki-Bauer. The clam was first observed in this region in 2008, when it was discovered in the Champlain Canal. Emily DeBolt, who directs the Lake George Association’s program monitoring boat launches for invasive plants and animals, said the Asian clam had never been observed that far north before that date.

“Lake George is now the most northern point in North America to be colonized by Asian clams,” said DeBolt. According to Nierzwicki-Bauer, the Asian Clam is no less dangerous to the lake’s health than Zebra mussels.  Like Zebra mussels, the Asian clam competes with young fish for food, clogs water systems and destroys ship wrecks. The Asian clam competes for habitat with the native clam, whose survival would be threatened by an invasion of the exotic mollusk, said Nierzwicki-Bauer.

Peter Bauer, the executive director of The Fund for Lake George, said that in some respects, the Asian clam is even more dangerous than the Zebra mussel.
“The Asian clam appears to intensify the decline in water quality by releasing nutrients and fostering the growth of algae,” said Bauer. The shells of dead clams can become a source of calcium for Zebra mussels and other invasive mollusks, creating micro-climates where the non-natives can mature and reproduce, said Nierzwicki-Bauer.  “It was a shock to learn that Asian clams had been discovered here because they’ve never been seen as a potential threat,” said Walt Lender, the executive director of the Lake George Association.  “The good news is that we’re working together to combat this threat as quickly and as effectively as we can.”
The Fund for Lake George, the Lake George Park Commission, the Lake George Association and Bateaux Below have agreed to help the Darrin Fresh Water Institute launch its efforts to combat the Asian clam, said Nierzwicki-Bauer.

“The Darrin Fresh Water Institute has proposed a first response strategy, which we need and which we should execute whenever something like this occurs,” said Mike White, the executive director of the Lake George Park Commission.  According to Nierzwicki-Bauer, that first response strategy includes determining the extent of the clam’s colonization and developing a plan to control it. “We’re sending divers to do an initial survey of the lake bottom; Dr. Dan Marelli is returning to Lake George, who will direct the surveys,” said Nierzwicki-Bauer. The Lake George Park Commission,  The Fund for Lake George and the Lake George Association will contribute to the initial costs of  responding to the threat, including the costs of retaining Marelli and other , said Nierzwicki-Bauer. The Lake George Association will make its Floating Classroom boat available to divers, said Walt Lender. Bateaux Below and The Fund will supply divers, said Peter Bauer.

“It is imperative that we move quickly to determine the extent of this infestation to assess the best treatment options that can be undertaken immediately,” said  Bauer.  “We have reached out to the regulatory agencies to assess all our options.”

The Darrin Fresh Water Institute,  The Fund for Lake George and the Lake George Park Commission are working with the state agencies to secure permits for eradication tools, said Bauer. According to the Fresh Water Institute and The Fund for Lake George, benthic mats have proven effective in controlling Zebra mussels in Saratoga Lake and Asian clams in Lake Tahoe.  Grants for rapid responses to invasive species are available from the Lake Champlain Basin Program, said Emily DeBolt.

A meeting of the scientists, lake protection groups and agencies participating in the response to the discovery of Asian clams was scheduled to be convened on Wednesday, August 25. Divers were planning to begin surveys of the lake bottom later that day.