Nearly 60 environmental advocates and officials from government and academia met in Great Barrington, MA to discuss the threat of zebra mussels in the Housatonic River. They also explored ways to coordinate efforts in both CT and MA to help stem the advance of this prolific invasive aquatic species.
The event, called the Housatonic River Watershed Zebra Mussel Forum, was the first of its kind in the area and attracted attendees from the Candlewood Lake Authority, Western Connecticut State University, the CT Dept. of Energy and Environmental Protection, the MA Dept. of Conservation and Recreation, private lake organizations, municipalities and FirstLight Power Resources.
“Zebra mussels do not recognize state boundaries,” said Dennis Regan, Berkshire Program Director for the Housatonic Valley Association, one of the co-sponsors of the Forum. “This issue needs to have a broad, watershed-wide perspective, and we were thrilled with the strong turnout."
“Watershed communities can and should get active in slowing the spread of this and any invasive species,” he continued. “Education is especially critical, since people want to do the right thing, but may not know exactly what to do. We need to coordinate our efforts, and be consistent with our message on a watershed wide scale.”
Larry Marsicano, Executive Director of the Candlewood Lake Authority, concurred.
“A significant part of the success of the forum was the sharing of ideas or measures that had been implemented in one state but not the other,” he said. “We came back with some new ideas or measures to possibly implement here. I'm sure some of the folks from Massachusetts also came away with some ideas that they might not have heard of, or thought about yet.”
Ethan Nadeau, the biologist who is credited with the October 2010 discovery of zebra mussels in the Housatonic River — specifically the impoundments of Lake Lillinonah and Lake Zoar — briefed the attendees on the status of the spread of the invasive species, both nationwide and in the Western CT and MA areas.
While acknowledging that the search for evidence of zebra mussels nearby has been limited and sporadic, he stressed that the spread is still very much in its infancy.
“The number of adult zebra mussels found at various locations is still very small,” he said, “And far more searches are negative, or turn up no evidence of zebra mussels, than those that are positive.”
He said more effort is needed to help detect and pinpoint the spread.
Nadeau added that he is not certain how the zebra mussels were introduced into the Housatonic River. Two theories exist. One centers on Laurel Lake, in Lee, MA, which is already contaminated and feeds into the Housatonic River. The other involves boaters who visited contaminated waters in other areas and did not take the necessary de-contamination precautions before entering Lake Lillinonah and Lake Zoar via boat ramps.
“This is not a temporary problem,” emphasized Phyllis Schaer, a CLA delegate from Sherman and the chair of the regional Zebra Mussel Task Force. “We all need to be personally responsible for the protection of our lake and resources. We need effective public awareness programs, with continued ongoing cooperation and support from the public, government and industry to prevent and control the spread of zebra mussels and other aquatic invasive species that threaten the health of Candlewood Lake and surrounding water bodies.”
Reproducing adult zebra mussels are hugely prolific, which is a key reason for the concern over Laurel Lake and its location near the headwaters of the 139-mile long Housatonic River. The river flows south from the Berkshire Mountains near Pittsfield, MA through western CT into the Long Island Sound.
A single adult zebra mussel can generate thousands of offspring, called veligers, which spend the first week to month of their lives drifting in the plankton, going where the current takes them. However, the microscopic veligers are also fragile and susceptible to water turbulence. Eventually, they settle out of the plankton, and attach themselves to hard surfaces, such as rocks, boat hulls and dock pilings, to grow and become adults.
Much of the Housatonic River is fast moving and may not be an ideal habitat for zebra mussels. The five impoundments on the river — located behind dams in Falls River, Bulls Bridge, Shepaug, Stevenson and Derby — as well as Candlewood Lake are more conducive to their survival and growth.
Last fall, Nadaeau, who heads a consulting firm called Biodrawversity, discovered adult zebra mussels further south on the Housatonic River, in the shadows of the Yale University crew docks, which are located on the southern end of the Lake Housatonic impoundment, in Derby, CT. Those zebra mussels were in approximately 11 feet of water and were at the end of their second growing season. Nadeau believes they may be the same cohort as the zebra mussels found earlier in Lake Zoar.
Education and Compliance
The second keynote speaker for the conference was Doug Jensen, the Aquatic Invasive Species Program Coordinator at Minnesota Sea Grant. He is an authority on invasive aquatic species in the upper Midwest and is especially experienced in public outreach efforts.
He reported on efforts to implement memorable boater education programs in Minnesota and to measure the impact of those programs on increasing boater awareness of the threat of invasive species and in encouraging compliance with procedures designed to limit the spread of zebra mussels, such as boat inspections and cleaning via boat wash stations.
Jensen encouraged the participants to utilize the existing and widely used “Stop Aquatic Hitchhikers” program materials. He also shared the results of attitude surveys which showed that “clear, frequent and consistent messaging via a variety of channels” was effective in increasing awareness, changing attitudes, boosting compliance with precautionary procedures and slowing the advance of invasive species.
New Control Strategies
The participants also discussed a few new management strategies for controlling the spread of zebra mussels. Meghan Ruta, Water Protection Manager for the Housatonic Valley Association and the co-coordinator for the forum, said one possible technique “included the use of carbon dioxide as a barrier to prevent the downstream migration of zebra mussel veligers.”
The carbon dioxide is released underwater via a bubbling system similar to that used to prevent icing around boats and docks in cold weather.
Another strategy involved the use of bacteria that specifically targets and kills zebra mussels without harming other aquatic species.
“A lot of investigation needs to be done before either strategy can be implemented,” she emphasized. “But it's important for all to know that there are some alternatives available to help stop the spread of zebra mussels.”
“It is always useful to meet with colleagues who are coping with and share our concern over the invasion of zebra mussels,” said Mitch Wagener, Ph.D., a professor in the Biology and Environmental Science Dept. at Western Connecticut State University. “This forum was very useful and provided several concrete ideas to help us improve our water monitoring efforts.”
Dr. Wagener leads a joint CLA/WCSU team involved in the early detection of zebra mussel veligers in Candlewood Lake and Lakes Lillinonah and Zoar.
Bard College at Simon’s Rock along with the HVA co-sponsored the full-day conference, which was held at the college’s campus in Great Barrington.