The Hydrilla Menace: Scientific coalition aids Salisbury’s lakes amid immediate and dire threat

This is the third of a series on invasive aquatic hydrilla and its growing threat to waterbodies and communities in Northwest Connecticut.

SALISBURY — Three pontoon boats loaded with passengers headed out into the open waters of East Twin Lake. This was no joy ride.

The boats’ occupants included members of a coalition of state and federal scientific and environmental advisers organized by the Twin Lakes Association (TLA) with urgency last summer after East Twin’s marina became ground zero for hydrilla.

On this day, scientists inspected thriving new colonies of the invasive weed which had taken root in areas of the lake up to 30 feet deep, a worrisome sign that despite efforts to control its spread with herbicidal dousing, the noxious weed is on the move.

“Here’s hydrilla! It’s huge!” announced Summer Stebbins, a research technician with the Connecticut Agricultural Experiment Station (CAES), pointing to a floating bed in deep waters. TLA member Rich Haupt slowed the boat so those aboard could get a closer look.

The pontoon excursions were part of a three-hour scientific meeting on Monday, Sept. 9 at O’Hara’s Landing Marina to help the affected lake chart a course for treating, controlling and managing the aggressive, non-native plant in 2025 and beyond. And it is not just the Twin Lakes in hydrilla’s crosshairs.

One stray fragment, or whorl, of the long, stringy plant can infect a waterbody. Once it arrives, it is there for good. Control and management are the only recourse.

The U.S. Army Corps of Engineers (USACE), New England District, is testing herbicidal cocktails at five sites along the ravaged Connecticut River Watershed, where this novel strain originated, the results of which may not be released until next year, according to Ben Sperry, research biologist with USACE.

In addressing the coalition, TLA President Grant Bogle was frank in his update on the battle to date. “We’re not ahead of this by any means. We’re getting beat up pretty bad.”

Salisbury’s six lakes

With six lakes within its borders, along with several ponds and a portion of the Housatonic River, Salisbury has a lot at stake.
“We’ve been pretty clear about how concerned we are,” said First Selectman Curtis Rand. “We spend about $50,000 on East Twin, but lately it’s been more because of hydrilla, plus $50,000 on Lakeville Lake and Long Pond,” for lake surveys and preventative measures, he said. He noted that costs are likely to rise as hydrilla spreads.

“They’ve done a lot of work in the management of Twin Lakes, and I’m there to support that,” added Rand, a coalition member.
The coalition roster includes, din addition to the TLA, the town of Salisbury, Northeast Aquatic Research (NEAR), CAES, CT Department of Energy and Environmental Protection (DEEP), O’Hara’s Landing Marina, Housatonic Valley Association (HVA), University of Wisconsin Whitewater, The Pond & Lakes Connection, SePRO, USACE, Salisbury School, The American School for the Deaf (ASD), and local government officials.

Building relationships, sharing information

The group is sharing research with stakeholders, including representatives of Lake Wononscopomuc, which swifly closed its boat launch once hydrilla was found in East Twin. In addition, Mount Riga Inc. closed its Ostrander beach and campsites as a precaution, but plans to reopen in 2025 with preventative measures in place and heightened public awareness.

Other Northwest Corner towns are also looking to Salisbury for guidance. Sharon selectman Lynn Kearcher attended the Sept. 9 forum to gather information.

“I have been doing research on hydrilla and we are very concerned it might invade Mudge,” the town official said of the 300-plus-acre natural pond in her town within the Housatonic River Drainage Basin. “We’ve got to be guardian angels of the lakes.”

Mudge Pond, Kearcher explained, “is so impacted with milfoil and curly-leaf pond weed that one more invasive plant would kill everything,” including the endangered wetland plant, bulrush, which thrives there.

During the three hour-forum, the TLA’s scientific partners offered support and guidance as the lake association grappled to find solutions that work to control hydrilla yet spare the rare native plants.

“Prop-grabbing risk”

George Knoecklein of NEAR, whose company performs lake surveys, pointed to the concerning “prop-grabbing risk” created by hydrilla beds that are being chopped up by boat propellers, leaving small fragments to drift away and repopulate.

New hydrilla beds, identified by a diver hired by NEAR, followed a path leading from the marina into the channel and beyond.
Gregory Bugbee, associate scientist at CAES, Office of Aquatic Invasive Species, noted that the Connecticut River variant is capable of growing an inch per day, and when water temperatures rise to about 80 degrees or higher, it can grow a foot per day.
Because East Twin is such a clear lake, hydrilla is able to thrive at maximum depths.

The group also discussed potential ways to protect West Twin, which flows into the ecologically sensitive Schenob Brook, including a possible lake draw-down of three feet and leaving benthic barriers in place as long as possible until the lake freezes.
“It’s critically important to keep it from getting over there,” said Peter Aarrestad, director of DEEP’s Inland Fisheries Division.

Solutions discussed included submitting permit applications to DEEP earlier, by year-end if possible, so approvals arrive in time to allow herbicidal treatment to start earlier in the growing season.

And while SonarOne remains the herbicide of choice, “we have to broaden that to be a systemic treatment” rather than a spot treatment, said Bogle.

“We don’t know what else to do at this point, frankly, so that’s what we are going to do,” said Russ Conklin, TLA’s vice president of lake management.

Stakeholders join in the battle

The American School for the Deaf (ASD), which operates a summer camp on Twin Lakes where campers enjoy the swimming and other aquatic activities, is “monitoring the situation closely,” ASD Executive Director Jeffrey Bravin said.

Bravin, who serves on the TLA Board, reported that while there have been no signs of hydrilla growth near the camp or beaches, “we will continue to monitor our beach, inspect our boats and communicate with the proper authorities should we notice any weeds resembling hydrilla.”

In the meantime, the school is educating its ASD community in West Hartford, he said, “to ensure that our staff and students who travel to Isola Bella are aware of the issue and can assist in proactive measures.”

At Lakeville Lake, the decision has been made that the “Launch Closed” sign will remain in place for the 2025 boating season, according to Bill Littauer, president of the Lake Wononscopomuc Association.

Mount Riga Inc. president Ana Maria Chrysler said while there was disappointment among town residents about this year’s beach closure, there was also “overwhelming support of our goal to protect Mount Riga lakes.”

Looking to next year, Chrysler said, “As of right now our intention is to re-open the Ostrander Beach,” with set hours of operation and monitoring, and heightened public awareness.

The coalition plans to regroup on Oct. 10 at 5 p.m. at the Town Grove on Lakeville Lake.

Bogle concluded the meeting by noting that the TLA is in the battle for the long run. “It’s going to be a game of cat and mouse for some time.”

A strand of hydrilla from East Twin’s Ohara's Landing Marina. Photo by Debra A. Aleksinas

How to identify hydrilla

Hydrilla is a submersed, multi-branched perennial herb, usually rooted but frequently with fragments seen drifting in the water. Leaves are vivid green and pointed with serrated edges.

Each plant grows in whorls of three to 10 along the stem, most often five whorls. Stems can be more than 35 feet long. The plant is often mistaken for native elodea (waterweed), although hydrilla presents as much more robust, stiffer and greener. While hydrilla generally grows from fleshy roots called tubers, the Connecticut River variant produces reproductive buds at the base of stems, called turions, which can remain dormant in undisturbed sediment for more than four years and require very little light to thrive.

Clean, Drain, Dry

After every boat outing, every time, clean off visible aquatic plants, animals and mud from boats, trailers and all equipment before leaving water access.

Drain motor, bilge, livewell and other containing devices and dry everything for at least five days or wipe with a towel before reuse.
For anglers, dispose of unwanted bait, worms and fish parts in the trash. Never dump live fish or other organisms from one water body into another.

Hydrilla Resources

Twin Lakes Association

For information on hydrilla visit twinlakesorg.org

Please email president@twinlakesorg.org to submit a photo of suspected hydrilla. Include name, date and location where photo was taken.

Connecticut Agricultural Experiment Station

For information on Aquatic Invasive Species visit portal.ct.gov/caes
Email: OAIS@CT.gov with photos of suspected hydrilla, with details on location.

U.S. Army Corps of Engineers,

New England District

www.nae.usace.army.mil/Missions/Protections-Topics...

CT Department of Energy and Environmental Protection (DEEP)

portal.ct.gov/deep/fishing/general-information/aquatic-invasive-species