Scientists with the Lake Champlain Basin Program have confirmed that there’s a new invasive species in Lake Champlain.
The golden clam — Corbicula fluminea — is native to the eastern Mediterranean and Asia, and can crowd out native species and lead to more toxic cyanobacteria blooms.
The mollusk has been in the region since 2008, but this is the first time it’s been identified in Lake Champlain.
“It is a clam that has a really dense shell, so it's unlike our invasive zebra mussel, where those shells become sort of brittle, and when they die back and you can crush them,” said Meg Modley, aquatic invasive species management coordinator for the Lake Champlain Basin Program. “The shell has these raised concentric ridges on the exterior. So if you ran your finger across the outside of the shell, it would make a clicking sound.”
A volunteer made the discovery when they pulled a suspicious clam from the lakebed near the South Bay boat launch in Whitehall, New York, last month, and notified local scientists.
The facility is located near the last lock of the Champlain Canal, where the clams have been found for several years.
Lake scientists from New York state and the basin program convened the Lake Champlain Rapid Response Taskforce last week to decide what can be done.
In those places where there are very, very dense populations of golden clam, there has been displacement of native species.Meg Modley, Lake Champlain Basin Program
The team of scientists has determined that further surveys and research are needed to understand how widespread they are in the lake and what impact they’re having.
Modley said the clams have proven destructive in other water bodies, wreaking havoc on infrastructure like dams and irrigation pipes and lines. But the big concern scientists here have is over their impact on the lake ecosystem.
“In those places where there are very, very dense populations of golden clam, there has been displacement of native species,” Modley said.
Of particular concern is the clam’s impact on macroinvertebrates and other creatures that function as the backbone of the lake’s ecosystem and tend to hang out in and around the lakebed.
Additionally, the clams are hermaphroditic, meaning a single individual can reproduce and start a new population very quickly in a new water body.
A case study in Lake George
The golden clam may be new to Lake Champlain, but scientists in the Lake George region have been contending with it for more than a decade now.
Dave Wick, of the Lake George Park Commission, said the clams don’t seem to like disturbance, which means they’ve had little impact on swimming areas in the lake.
“The long and short is, thankfully, so far no significant recreational or ecological impact, but we do see them expanding throughout Lake George more and more every year,” he said.
He says the commission has spent millions of dollars to mitigate the clams and monitor for them, with mixed success at controlling their populations.
The first year they were identified, they rolled out a pool liner by the acre in areas of the lake where the clams had been identified.
The clams came right back, and Wick said they’re still looking for ways to control them.
Of particular concern is that the clams are sensitive to cold water. Lake George is warming rapidly year over year, due in part to human-caused climate change.
Modley, with the Lake Champlain Basin Program, said warmer water temperatures could help the clams spread faster in Lake Champlain.
“We are seeing our winters are milder. We have less ice-over on the lakes in the region. Lake Champlain hasn’t frozen over in three years, and if we continue on this trajectory, we may have waters and environments that are more suitable for this … species,” Modley said. “So it may help to facilitate the expansion of this species in the Northeast.”
The Lake Champlain Basin Program is asking boaters to be especially careful to clean their boats and ballasts after recreating in Lake Champlain.
The clams have also been identified in Lake Bomoseen.
Additionally, Modley said they’re recruiting volunteers for the Champlain Aquatic Invasive Monitoring Program, to help look for the clams in other parts of Lake Champlain.
The discovery of golden clam brings the total number of invasive species in Lake Champlain to 52.
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