Scientists Studying Movement of Asian Clams Throughout Lake
It’s a reasonably well-established fact that Asian clams were introduced to Lake George by human beings, most likely through boats or fishing gear, or perhaps even from an aquarium that a resident or visitor had tired of and dumped into the lake.
After the invasive species was discovered near a Lake George Village beach in 2010, it soon spread to other parts of the lake. Most populations were found near other launches, where they were, in all likelihood, introduced by boats that had never been decontaminated.
But some clams infested the waters near the site where they were first discovered and still other, smaller colonies were found in remote sections of the lake, far from any boat launches.
How they got to those sites, and how Asian clam populations spread, are questions that researchers from the Darrin Fresh Water Institute sought to answer through a number of experiments conducted for the Lake George Park Commission.
One experiment sought to determine if sediment attached to boat anchors contained velligers that were then moved from one site to another when the boat anchored at a different location. The researchers concluded that anchors were possible vectors.
“If boaters aren’t diligent about cleaning sediment from their anchors and lines, then, in these cases, it’s possible they transported the Asian clam to other sites,” said Dr. Sandra Nierzwicki-Bauer.
The researchers also investigated the possibility that Asian clams might become attached to plants, which, when they die, float to the surface and are borne by winds and currents to other locations.
“We hypothesized that Asian clam juveniles may use this floating plant mass as a vector for transport over long distances within Lake George,” said Dr. Jeremy Farell, the researcher who is credited with discovering Lake George’s first Asian clams.
The researchers concluded that floating plants were not a primary means of transport.
Winds and waves are probably moving colonies from one site to another one nearby, the researchers said.
They found that even adult Asian clams can be suspended in the water column, from which currents, winds and waves can transport them to new locations 65 feet away.
“Once a clam spawns, it can be re-suspended in the water column, and if a mature clam moves, there’s a greater likelihood that it will reproduce,” said Nierzwicki-Bauer.
According to Dave Wick, the executive director of the Lake George Park Commission, large-scale efforts to eradicate Asian clams have been suspended until more information about the transportation of the Asian clam and its spawning habits becomes available.
“No effective management is possible until we have clear answers to these questions,” said Wick.
In the mean time, some actions could help slow the spread of Asian clams, said Lake George Park Commissioner Dean Cook.
“I suggest we establish no-anchor zones in any sites infested with Asian clams. If they’re being spread by anchors, then at least we can stop that,” said Cook.