A problem, answered by a plan and some tentative options, surrounds a growing invasives issue in Lake Lillinonah.

“There is no permanent solution; you’ll never get milfoil out of the lake — you’re not going to get rid of it; it’s about management,” said Larry Marsicano, principal limnologist with Branford-based Aquatic Ecosystem Research (AER).

Recently, the Friends of The Lake (Lillinonah) hired AER for an invasive species management plan, 44 pages that provide thorough research and background for several means of invasives management, including chemical treatments, introduction of carp into the lake, and machine harvesting to address milfoil, zebra mussels, and other species.

Both the Friends of The Lake and Lake Lillinonah Authority (LLA) members offered statements in response to the plan, and both indicated they were opposed to chemicals. The LLA and FOTL mentioned the possible pursuit of introducing sterile carp, which will require state permits.

FOTL board member and Newtown resident Scott Conant confirmed that “carp are the preferred method, but there are financial and regulatory hurdles to overcome. But we will pursue” the carp.

“We are trying to accomplish a long-term solution — something that will last for years and be sustainable and chemical-free and bio-friendly.” He noted that “all methods have benefits and drawbacks. Chemicals work quickly,” but he would rather not see chemicals introduced to the water. “Although cost effective, there are significant downsides.”

Mechanical harvesting “is also something we are looking at,” Mr Conant said. “That gets things out of the lake without chemicals, but costs are rather high as well. That leaves us with carp.”

Bringing carp into the lake may require other changes. “There may be modifications needed to the infrastructure of the lake to contain the carp at openings at different tributaries,” Mr Conant said. “We would have to close off Still River, for example. That could also be cost prohibitive.” He said other area lakes “are having the same problem… so we will probably present this as a Housatonic River issue rather than just Lake Lillinonah.” There “is an intention to talk with other stakeholders, and we have a list of other parties and will contact them in the near future.”

Regarding the AER plan, “We were able to provide them a list of options,” Mr Marsicano said. The approach is similar to what the Candlewood Lake Authority “went through years ago,” when he was part of that entity.

Dr Mark June-Wells and Larry Marsicano of AER combined their knowledge, experience, and research to develop the Aquatic Ecosystem Research (AER) Integrated Plant Management Plan 2018 and its findings.

“This plan was an approach to the whole lake and to focus on sites that were impinging on recreational use. We looked to manage the areas of high recreational value,” Mr Marsicano said.

FOTL And LLA Respond

Following a forum hosted by Friends of the Lake on Friday, September 28, to present the “results of a study and management plan,” according to a recent notification from Friends of the Lake Executive Committee member George F. Walker, both Friends of the Lake and the Lake Lillinonah Authority issued statements.

The LLA statement concludes, “The LLA has, in the past, used chemical measures in an attempt to control [milfoil] but found this measure to be ineffective for long-term management. We have also become concerned about the long-term consequences of using chemicals on the environment as well as the users of the lake; hence, we have stopped such treatments. We are opposed to the use of chemicals as a long-term management plan.

“After evaluating the given options, the LLA is advocating the introduction of triploid carp (sterile grass carp) as the preferred management measure... We are also in support of measures that do not involve the use of chemicals...

“The LLA believes that education and community cooperation are our greatest strengths when used properly.”

The FOTL statement issued in late September says, “The plan does an excellent job describing the exponential growth of invasive aquatic plants in Lake Lillinonah during the last decade. It is clear from our experience and from the evidence presented in the plan that invasive plants, especially Eurasian Milfoil, is a problem that has reached a point where something must be done to reduce their volume in the lake to improve the recreational, safety, and aesthetic qualities of our lake.”

As stated in the LLA’s response, “The LLA is committed to the health of the lake and realizes that there needs to be a comprehensive plan for the management of the invasive species. Invasive species are a fact of the lake’s existence and management of these requires careful attention by all involved.

“The LLA realizes that there are many parties with varying interest in the lake (homeowners, fisherman, boaters, kayakers) and must balance their interests.” Charged with “overseeing the environmental, safety, and recreational needs of Lake Lillinonah,” the LLA “sympathizes with property owners that deal with the nuisance of the Eurasian Watermilfoil and hear from the fisherman about its importance for fish habitat. There are other users of the lake that have expressed concern about the use of chemicals in the lake.”

The statement continues: “The LLA is working towards addressing all the concerns but realizes that we will likely not be successful in satisfying all parties involved. We have to balance the needs and safety of the lake users as well as maintain the health of Lake Lillinonah.”

Current invasives include zebra mussels, water chestnut, curly leaf pondweed, and Eurasian watermilfoil.

Further paragraphs discuss each invasive. The statement ends with an appeal for “education and community cooperation …”

Also seeking a “unified approach,” the FOTL statement says, “We are concerned that individuals or groups of homeowners will use a variety of chemical treatments in a ‘scatter-shot’ approach to reduce the plant infestations. We believe that a unified approach will be a safer, more effective, and longer-term solution to this problem.”

FOTL members also stated that they are opposed to using chemicals for a host of reasons, like that it is just a temporary solution, after which the plants grow back and require more chemicals.

In its statement, FOTL speculates on “What else to do?”

“The plan suggests grass carp as a possible solution but notes that there are significant permitting hurdles and infrastructure changes that could be required. Friends of the Lake intends to pursue this solution” on a state level “to try and obtain the required permits and determine what infrastructure changes would be needed and at what cost. Grass carp are not inexpensive, and subject to escape and population collapse, but offer a natural solution to our problem. Candlewood and other lakes have had success with grass carp as a solution to milfoil infestations.”

Friends of the Lake states it will “research the true costs of owning and/or operating mechanical harvesting equipment. The problem with mechanical harvesting is the initial and/or ongoing expense. The benefit is that harvesting removes the material from the lake without chemicals involved.”

FOTL members “will work diligently to pursue a non-chemical treatment program to reduce the invasive plants in Lake Lillinonah while keeping the lake as clean and chemical-free as possible.”

What Has Changed

What has changed in past few years? “There was the suggestion that the zebra mussels were cleaning up the water and letting sunlight in…” and boosting plant growth, said Mr Marsicano. He said that “milfoil and plants in general even in Candlewood, there can be a large bed in one place one year and not another… but the area it was occupying was increasing.”

The plan was “pretty clear; there is no permanent solution.” He suggested, “It’s permanent management,” that is necessary. But what does that involve? He asked, “is it something biological or herbicide? Getting rid of it is just not going to happen. Once it is established … it’s a dominant plant.”

Also, he said, “One thing we advise in the plan we presented is if you treat the milfoil, another plant will fill the niche.”

Mr Marsicano said, “There are ways of keeping up with milfoil on a small-scale, but large-scale is different — even large-scale, you’re not going to get rid of it; it’s about management.”

Regarding the carp, he said there is an attrition rate, and they require stocking… that, too, is ongoing management.

If the FOTL and the LLA want to pursue the use of carp, “they are going to have to engage the state, and there will need to be funding.”

Lake proponents “will need a permit from the state to put carp in the lake. They will have to submit an application. They will have to have a heart-to-heart discussion at a state level,” Mr Marsicano said.

“In the past, the state has been reluctant… when you can’t ensure that you can keep the fish in the system you are trying to manage — that’s the challenge — you have to have written approval from anyone who owns property under the water… and second, ensuring biological isolation. In this case, you don’t want them throughout the Housatonic River; they’re not native either.”

The plan offers “a look at all the options, and the community needs to figure out what they want to do.”

Both the FOTL and LLA did due diligence, he said.

The Plan

The plan’s executive summary states, “eradication of all non-native plants is improbable, and attempting to reach such a goal would be detrimental to recreational and ecological values of the lake.” Researchers also focused on priority treatment areas in proximity to residences and recreational assets.

From the summary: “Coverage of Eurasian Watermilfoil appears to be increasing exponentially, and in AER’s opinion, is the highest priority non-native plant to be managed.”

The summary also mentions the presence of water chestnut and curly-leaf pondweed.

AER has developed a three-year, integrated plan for Lake Lillinonah, including the use of herbicides, which the LLA did not wish to pursue; mechanical harvesting for Mino Naiad; and hand-pulling water chestnut.

The plan goes on to discuss many aspects of Lake Lillinonah, the various invasives, and years of data collected.

The plan presents management options, costs, benefits, risks, and effectiveness.

Friends of the lake is a nonprofit organization founded in 2003 to improve Lake Lillinonah for the recreational enjoyment for those who use it, to improve its water quality to the standards set forth in the Clean Water Act, and for the long-term environmental protection of this beautiful section of the Housatonic River and its watershed

According to aerlimnology.com, “Our goal at AER is to optimize lake and reservoir conservation practices through research, education, and public outreach. We achieve these goals by working with lake associations, water authorities, state agencies, and municipalities to develop effective, fiscally responsible management plans.” The company is based in Branford.