Barriers in place at East Twin to thwart ‘Godzilla of invasive plants’

SALISBURY — In mid-April the state Department of Energy and Environmental Protection (DEEP), at the urging of the Twin Lakes Association (TLA), placed a line of boulders at the state boat launch to prevent trailered boats from accessing East Twin from that location.

They didn’t stay put for long.

Within a few weeks, unknown individuals had moved the hefty rocks aside, “presumably to allow boaters to launch there once again,” the TLA noted in its recent newsletter, and as evidenced by tell-tale tire tracks leading to the water.

Alerted to the boulder breach by the TLA in late April, DEEP officials returned to the state boat launch on May 6 to put them back into position, this time burying them deep into the ground to deter movement.

“This launch was never intended to be used by trailers, is unimproved and has been returned to its original use as committed to the TLA in 1991 by the state, for car-top carrier boats only,” such as kayaks and canoes, explained Grant Bogle, the lake association’s president.

He noted that in 2020 the boulders were removed by the state to provide greater access for handicapped boaters, which led to a “significant increase” in trailer access and parking issues in recent years.

“In addition, we believe hydrilla was brought in via boat at the state launch,” as well as the nearby O’Hara’s Landing Marina, where patches of the invasive plant were discovered last summer, said Bogle.

The findings made East Twin the first of about a half dozen Connecticut lakes to become infested with the aggressive hydrilla variant which has been wreaking havoc on the Connecticut River for several years. Its discovery prompted rapid response by the TLA and a coalition of scientists, biologists, environmentalists and state and local lawmakers to stop the non-native plant from overtaking Twin Lakes and contaminating other bodies of water.

“Hydrilla is the Godzilla of invasive plants,” said Bogle, noting that it is the responsibility of everyone who uses the lake to become its guardians.

“It is very aggressive and will outcompete native species,” he explained. Scientists describe hydrilla as one of the “world’s worst’ aquatic weeds.

“It alters the oxygenation and chemistry of lake systems, which may negatively impact fish and other native lifeforms,” noted Bogle. “It forms thick mats that are nearly impossible for boats to traverse, and there is a risk that wildlife like bald eagles, which are present on Twin Lakes, may ingest hydrilla which may contain a neurotoxin that can be fatal.”

The state boat launch was sanctioned years ago as an entry point for roof-top vessels, and the threat from hydrilla prompted the TLA to ask the state to restore that status and return the boulders to ensure that all boats entering the lake from a single point can be monitored.

A boat launch monitoring program is now in place at O’Hara’s Landing Marina under the direction of the TLA and the town. The goal of that effort is to greet boaters and alert them to the hydrilla threat, distribute educational materials on best practices for preventing spread of the invasive weed, and make a visual inspection of boats entering and leaving the marina.

Other measures are in place this year to suppress hydrilla growth as it begins, typically in June.

TLA board members Rich Haupt and Russ Conklin recently installed a barrier under the Isola Bella bridge. The modestly lit “limno” barrier, with its neon yellow float holding it in place, is designed to keep hydrilla fragments from following the natural current from the northeast cove, where the invasive plant has been identified in multiple places, to the northwest cove.

While lake association officials recognize that the barrier, which they said will not impact natural lake rhythms, is an inconvenience as it blocks passage for kayaks, canoes and swimmers, it is only a temporary fixture until hydrilla is under control.

Earlier this month a team of scientists, joined by TLA directors, toured the lakes to assess the hydrilla threat and discuss treatment strategies. While no hydrilla was found this early in the season, there was agreement that it will begin to show itself by July.

Keith Hannon of the U.S. Army Corps of Engineers noted that he is running six pilot tests of herbicides in the Connecticut, and initial data will be available by the end of the year.

Bogle suggested that those who doubt the challenges posed by hydrilla view a video released by the U.S. Army Corps of Engineers showing the damage that it has done to significant parts of the Connecticut River as well as an article in the science journal Invasive Plant Science and Management, which offers new insights on hydrilla verticillata, also known as water thyme, taking root outside the Connecticut River including East Twin Lake.

Jeremiah Foley, an assistant agricultural scientist with the Connecticut Agricultural Experiment Station (CAES) and lead author for the study, noted that “The discovery of Hydrilla verticillata and its subspecies lithuanica in the Connecticut River, and the breadth of the current infestation represent a significant ecological invasion event with potentially far-reaching implications.”

Both the video and research paper are posted on the TLA website, www.twinlakesorg.org.