Hanover Road resident Scott Conant has witnessed a “huge change” in the invasive zebra mussel population in local waters this year. He has seen the numbers increase from “just a few two summers ago, to many last year, to an explosion this year,” he said in a recent e-mail.

A Friends of The Lake (FOTL) board member living along Lake Lillinonah’s shore, Mr Conant first sent the alert to other members in late October after inspecting the underside of his dock.

“The bottom of our dock was completely encrusted this year,” he said.

Mr Conant estimated thousands of mussels last year, and that number has greatly increased, he said. “Interestingly, there aren’t that many on the rocks at the bottom of the lake, though I suspect that will come.” While the lake water level was low in past weeks, he looked through the rocks where he saw “many” mussels, “but not encrusted like the bottom of my dock.” He said that they were “more plentiful on manmade objects,” to which larval mussels may adhere more easily.

Living along another of Newtown’s lakes with both public and private access is Lake Zoar Authority Chairman Ray Hoesten. He said of zebra mussels last week, “We’ve got them bad this year.”

When Mr Hoesten, an Underhill Road resident, took his boat out of the water in early November, he said he saw them underneath the boat.

Regarding their infestation, he said, “We have been following them now for a few years.” Mr Hoesten also feels that boats carry zebra mussels from other lakes into Newtown’s waters.

Mr Conant said, “We would not take our boats to another body of water without a thorough drying.” He suggested: “Flush the motor with fresh water and dry the boat thoroughly, for days if not longer, including trailer beds, before going to another body of water …Friends of the Lake is keeping up with zebra mussel reports, and further study “should present some answers for us all,”

Mr Conant said. “To our knowledge, there is no effective method of eradication to date.”

With a similar statement, Mr Hoesten said, “Right now we don’t have a system to solve the problem.”

The LZA has been working closely with Western Connecticut State University biology professor Mitch Wagener, PhD, for the past several years, trying to find ways to manage this problem.

During an interview last week, Dr Wagener offered an overview of the work that has already taken place in the last three years, and the details he has learned about the mussels now infesting Lakes Zoar and Lillinonah, where their populations “are growing.” So far they have not been detected in Candlewood Lake, but that may be “just a matter of time,” Dr Wagener said.

In efforts supported by the Department of Energy and Environmental Protection (DEEP), Dr Wagener has looked for larvae in the lakes, and colleagues and students have looked in the Housatonic as well, “to find where mussels are coming from.”

Twin lakes near the Housatonic River in the northwest corner of Connecticut and lakes in or near Lee, Mass., have caught Dr Wagener’s attention.

“We are not sure that the twin lakes are a viable source because it’s not clear how [mussels] get from the lake to the river,” but the lakes in Massachusetts might prove a more likely source. Those “potential sources” are connected to the Housatonic River by stream and pipe. “So, there is a hydrologic connection,” Dr Wagener said. “Chances are good that’s where they are coming from.”

Regarding mussel populations in local lakes, volunteers and researchers are using “mussel hotels,” which are materials that provide an optimum surface for mussels, which are “introduced to lake.” The “hotel” is a good place for the adults to settle, Dr Wagener said.

“The idea is, we hang them at optimum depths and leave them there from early summer until late October and get an idea of how many and what size adults are settling out,” said Dr Wagener, who has yet not seen results from October.

He and others will continue to monitor population and see what affect it’s having on water ecology.

Is There A Solution?

Dr Wagener hopes a study will take place as soon as next year in Lee. Researchers are looking at a way to kill mussels, “So they can’t colonize in the Housatonic,” he said. DEEP is supporting the project and in part funding supplies and equipment.

“If it’s successful, it will show that [mussels] can be prevented from entering Housatonic,” Dr Wagener said. He has seen other scientists’ studies show that the zebras “have a big impact at first, change river ecology, then decrease in number and the river comes back, but not the same as before.”

Dr Wagener said, “If we stop the mussels from getting in, the population will decrease and they will be more manageable,” but he believes they are in local waters for a long stay.

Noting the “ecological effects” from the mussels, Dr Wagener said, “the lakes remain clearer,” but there will be “millions of these little clams on hard surfaces and you won’t want to walk barefoot.” He said, “Lakes will be more friendly to invasive plants, and the fish communities may change in terms of what fishes are found.” Carp, for example, “love these things.”

He said, “On the surface [changes caused by the mussels] will please people, because water is clearer, but the more the lake is open, the more the weeds can grow,” Dr Wagener said.

A certain form of plankton is reduced as it competes with mussels for food.

“The more food eaten by mussels, the less there is for the plankton and the fish that eat that plankton,” he said.

Sunfish and ducks or carp will eat the mussels, “but not fast enough to keep them in check,” he said.

Looking several years ahead, he said the mussels “are like house sparrows or starlings; they are a part of the environment now, and it will be a matter of how we manage them. They will be a big bother. People will not be happy clearing out their outboard motors or docks clogged with these little clams.”

The mussels “are a nuisance,” Dr Wagener said. They attach to boats and docks, he said. “It’s a nuisance to clean them off, they’re fouling organisms, and populations are growing fast.”

A Solution?

Working on the problem and an upcoming test with Dr Wagener and others is Candlewood Lake Authority Executive Director and fresh water ecologist Larry Marsicano.

“We have our fingers crossed,” he said last week, about a field project that he hopes can begin next spring and early summer “when the mussels start spawning in May and by June are in full spawning mode.”

He spoke about a testing method that could work to reduce or kill off zebra mussels in the larval or plankton form. If it works, he said, “It gives hope to a lot of places throughout the country” that are dealing with zebra mussels on a much larger scale.

Testing will take place at a lake in Lee.

Mr Marsicano explained that by injecting carbon dioxide (CO2) in the water to change ambient levels, “you can kill adult [mussels] and veligers.” The CO2 is introduced at a pinch point — a spillway or small stream leading from a contaminated source to a place “where you want to keep them out of.” If the experiment works, he said, “over time could see populations entrenched at Lillinonah and Zoar slowly decrease.”

The CO2 will lower water’s Ph, “not to a level where it’s detrimental to life, but only harmful to larval shellfish,” Mr Marsicano said. “A level completely fine for most freshwater organisms in the New England area” is harmful for shellfish, he said.

The experiment would entail setting up a field experiment where “we would inject CO2 into pipes leading to the Housatonic and see how many veligers go in and how may live veligers come out.” He already has federal and local permits and commitments from the DEEP and Dr Wagener and his students and others, but still needs to finalize agreements with private and corporate partners before beginning the testing.

In 2009 residents found populations in lakes in Lee Mass and in 2010 the mussels were found in Lillinonah and Zoar.

“Since then, populations have become exponential,” Mr Marsicano said.