Salem ― A citizen scientist has raised the alarm that an aquatic weed wreaking havoc on the Connecticut River has come to Gardner Lake.

Kate Johnson, a self-described lake advocate and a former member of the Gardner Lake Authority, said she was in the water with her husband outside their Montville home on July 15 when she saw a very green weed floating by.

“I collected it, and my heart sank to my stomach,” she said. “It looked like hydrilla.”

Hydrilla was first identified in the Connecticut River in 2016 in Glastonbury, according to The Connecticut River Conservancy. It has grown to cover more than 70 miles as it continues to degrade water quality, choke out native plant species and threaten the habitat for migratory fish like shad and herring.

Connecticut Agricultural Experiment Station associate scientist Gregory Bugbee said Johnson immediately alerted him to her discovery in the 529-acre lake.

“I was there the next day,” he said. He arrived at the state boat launch with a boat outfitted with underwater cameras.

“Once we started going around the ramp in 6-8 feet of water, we saw hydrilla,” he said.

He said he identified the invasive plant at all ends of the lake, though he said the volume at this point is not extensive in most areas.

“It’s in the shallow coves and in the east, south, north and west,” he said.

Left unchecked, the weed described by U.S. Sen. Richard Blumenthal as “the worst invasive aquatic species known to man,” can make waterways impassable.

Hydrilla ― which is considered especially resilient because it spreads through fragmentation, which is a form of asexual reproduction or cloning ― can travel from one water body to another on boats and jet skis if the vessels aren’t properly cleaned, drained and dried before being placed in the water. Hydrilla can also enter a lake on sea planes and geese.

Bugbee this week was awaiting DNA testing on the weed to confirm suspicions that hydrilla in Gardner Lake represents the same strain plaguing the Connecticut River. The scientist and his colleagues have said the strain, unique to the northern part of the United States, is in many ways more resilient than other hydrilla strains.

A unique strain

The hydrilla species as a whole has been framed by politicians as a monstrous mass capable of growing 100 inches per day while playing host to cyanobacteria that can punch holes in the brains of eagles. Among the lawmakers are state Rep. Christine Palm, D-Chester, who was integral in the creation of the Office of Aquatic Invasive Species in 2022 for about $600,000 per year. Blumenthal over the past three years has touted more than $12 million in federal funds dedicated to controlling hydrilla.

The unique strain found in the Connecticut River ― and now in the lakes ― is the subject of study by the agricultural experiment station and the U.S. Army Corps of Engineers as scientists seek to understand the plant’s biology and how to manage it.

So far, northern hydrilla is understood to be hardier than the southern strain because it produces more bud-like structures that can break off the plant and reproduce. It also appears to tolerate colder temperatures better.

That’s not good news for the eight Connecticut lakes where northern hydrilla has been identified so far, according to Bugbee.

“Certainly, if the hydrilla in Gardner Lake adheres to the characteristics of the Connecticut River hydrilla, there’s a likelihood that the shallows would become impassable,” he said, referring to areas about six feet deep or less.

He could not speculate on how fast the hydrilla population in Gardner Lake could grow.

“It could be as little as a couple years, or maybe it could remain rather innocuous,” he said. “All of this is completely unknown, but in some ways you can’t really take the chance that it’s going to be innocuous.”

He said one encouraging sign is research indicating the northern strain, unlike the other strains, does not appear to reproduce by tubers ― or seeds ― that end up in the sediment at the bottom of the lake where it’s more difficult for herbicides to reach.

Bugbee described the lack of seeds as a biological “weakness” of the northern strain that scientists might be able to exploit. If the vegetation can be controlled before buds break off in vast quantities, which he said happens sometime in August, it might be possible to prevent the next year’s infestation.

Gardner Lake Authority Chairman Henry Granger Jr. did not answer a request for comment about what the next steps might be.

Information gathering

According to Bugbee, there was no evidence the northern strain existed in the state outside of the Connecticut River until last year. That’s when reports began to come in about the presence of hydrilla in lakes across the state, including nearby Amos Lake in Preston, Lake Pocotopaug in East Hampton and more recently at Bashan Lake in East Haddam.

He was hopeful the situation in the lakes could benefit from a project happening now in partnership with the U.S. Army Corps of Engineers to determine which herbicides ― and in what quantities ― will best control the spread in the Connecticut River. Test sites include Selden Cove in Lyme, where an herbicide application is set to begin the week of Aug. 5.

Bugbee said a $43,000 grant through the state’s aquatic invasive species grant program will help the agricultural experiment station survey lakes around the state’s 94 inland freshwater boat launches for the presence of hydrilla.

“Right now we’re gathering information,” he said. “We’ll have more information on these tests the Army Corps of Engineers is doing on the river with herbicides so we can put it all together and see where can we go.”

He was also hopeful his agency could secure federal funding to help manage the problem.

He acknowledged any type of herbicide use is controversial and expensive.

The price tag for any given lake could range from the tens of thousands of dollars to hundreds of thousands, according to the scientist.

His agency has reported the cost to treat the 378-acre Coventry Lake back in the early days of a hydrilla infestation was about $100,000 a year. Meeting minutes from an April 2024 Coventry Town Council meeting detailed six years of treatment that by 2023 had failed to fully eradicate the plant, though it had been eliminated in some areas. Now, lake scientists are again recommending an herbicide treatment be applied for three years at a cost of $119,750 per year.

Clean, Dry, Drain

Johnson, the lake advocate who first brought the presence of hydrilla to the state’s attention, said opportunities to kill off aquatic weeds in the shallows have been missed because annual drawdowns conducted by the state Department of Energy and Environmental Protection (DEEP) have not lowered lake levels by the desired 3 feet.

She said the drawdowns, which are funded by the Gardner Lake Authority, are intended to drop the lake level so water recedes about 25 to 30 feet from the shoreline.

Lowering lake levels helps kill off shoreline weeds, control downstream flooding during the early spring rains, prevent shoreline erosion and protect personal property.

“We need to get the state on board and treat this as a model for the state,” she said. “Give us our full drawdown this year and see if that helps to manage the hydrilla.”

DEEP spokesman Ethan Van Ness in an email acknowledged invasive plants like hydrilla are a serious problem for the health of lakes nationwide.

He said drawdowns may have an impact on aquatic invasive plants, but under specific circumstances depending on the species being targeted.

“Hydrilla being found at depths of 6 to 12 feet, as reported by the Connecticut Agricultural Experiment Station, would require deep drawdowns at those depths, which would have negative impacts on fish, aquatic organisms, and native aquatic vegetation.”

Van Ness said lowering the lake levels is challenging because “success is weather dependent.” He pointed to significant amounts of rain during the winters of 2022 and 2023 that prevented drawdowns from meeting the depths that were planned at Gardner Lake and other locations.

Johnson also wondered if closing the state boat ramp to prevent the spread of hydrilla could become necessary.

Van Ness said the answer was no.

“Providing equitable public access to state waters for all Connecticut residents is a critical part of DEEP’s mission,” he said. “DEEP therefore has no plans to close a public boat launch because of the challenges associated with aquatic invasive species.”

Signs went up this week to emphasize to boaters the importance of cleaning, draining and drying their vessels to prevent the spread of hydrilla. That means cleaning plants and debris from the boat and draining all water before leaving the launch, and drying or washing it at home prior to putting it in the water again.

Bugbee said the agricultural experiment station is working with the DEEP to investigate putting boat cleaning stations on high risk ramps to be used for boats going in and out.

DEEP boating education assistants are stationed at boat launches across the state on weekends to teach boaters about the threat and how to prevent the spread. They can also conduct vessel safety checks that include looking for signs of invasive plants.

The vessel safety checks are voluntary and DEEP education staffers don’t have enforcement powers.

Bugbee and Van Ness agreed the best approach to management of the spread of all aquatic invasive species ― including hydrilla ― is through education and outreach to boaters.

e.regan@theday.com