In December 1999, researchers discovered that Lake George was not immune to Zebra mussels after all.

During an annual dive to retrieve litter from the lake bottom in Lake George Village, volunteers discovered what appeared to them to be the exotic mollusk that had already wreaked havoc in Lake Champlain and in nearby rivers, competing with native animal species for food and clogging water systems.

Diver Joe Zarzynski contacted the Darrin Fresh Water Institute, whose scientists confirmed that the brown and cream striped shell attached to a beer bottle was indeed a Zebra mussel.
While a lone Zebra mussel is relatively harmless, its appearance usually indicates the arrival of thousands of the unwanted visitors.

“My God we’ve been invaded!” the Darrin’s associate director, Chuck Boylen, recalls thinking.

“We went through denial, depression, to finally dealing with it,” Boylen said.

Ten years after that initial discovery, Zebra mussels have yet to successfully establish themselves in Lake George, says Darrin director Sandra Nierzwicki-Bauer.

“Even with all the lakes nearby, and the multiple opportunities for introductions, Lake George has not become infested with Zebra Mussels,” said Nierzwicki-Bauer. “One reason for that is the quick response in December, 1999.”

That “quick response” was a massive volunteer effort that hand harvested more than 90 percent of the mussels from the site.

Dive teams removed more than 21,000 Zebra mussels from a 1,500 square foot area off the new Lakefront Walkway.

“If we didn’t do something before spring, when Zebra mussels spawn, we would have lost our window of opportunity, “ said Nierzwicki-Bauer. “Only two ideas surfaced. We could have erected a dam containing the site, but that would have required valuable time getting permits. Or we could remove them by hand.”

That effort not only saved Lake George from a permanent infestation of Zebra mussels; it has provided scientists around the globe with a promising example of how Zebra mussel populations can be successfully controlled without damaging the natural ecosystem.

“Conventional wisdom on Zebra mussels holds that once a population is established, they are impossible to control,” said Nierzwicki-Bauer. “However, we have been able to show that it might be possible to remove enough mussels to reduce the population density to the point where successful reproduction can be impeded.”

The results of the Lake George effort, based on the activities and studies of divers and scientists from 1999 through 2007, were published last summer in the journal Aquatic Conservation: Marine and Freshwater Ecosystems.

“We’ll never know for certain how Zebra mussels were introduced to that site or what created the micro-environment that allowed them to flourish,” said Nierzwicki-Bauer.

Zebra mussels can be easily introduced to the lake by “hitch-hiking” on boat hulls, in bilge water or in bait buckets.

But for Zebra mussels to mature and reproduce in Lake George, the lake’s water chemistry must be altered.

“Although there are a number of factors indicating that Lake George provides a less than favorable environment for zebra mussel colonization, micro-environments can be created by storm water, construction or even heavy equipment,” said Nierzwicki-Bauer.

Since 1999, eight new colonies of Zebra mussels have been discovered in Lake George.

Following the precedent established in 1999, each site has been systematically cleaned by divers.

Hand-harvesting sites while populations are relatively small has been complemented by public education, inspections at boat launches and surveillance of sites where Zebra mussels are likely to be found.

“Perhaps ‘mission accomplished’ can never be claimed in the fight against Zebra mussels, but the prevention of colonization may well be possible with a long-term commitment to monitoring and rapid removal,” Nierzwicki-Bauer said.

Photo: Chuck Boylen, associate director of the Darrin Fresh Water Institute, confers with divers hand harvesting Zebra mussels in Lake George Village in December, 1999. Lake George Mirror file photo

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