For many years it seemed that nothing would stop the spread of Eurasian watermilfoil in Candlewood Lake, but 2017 might prove to be a turning point.
Some coves on Candlewood and neighboring Squantz Pond had virtually no milfoil this year — a stark contrast to previous years, when the invasive weed fouled boat propellers and tangled the limbs of unwary swimmers.
“In portions of the lake, it was a complete 180,” said Larry Marsicano, the former executive director of Candlewood Lake Authority who now works as a consultant.
The news was not so good in nearby Lake Lillinonah. Greg Bugbee, who oversees the Invasive Aquatic Plant Program for the Connecticut Agricultural Experiment Station, said milfoil infestation on that lake is “the worst I’ve seen it.”
Bugbee noted these stark differences while mapping the plants this summer on all three bodies of water.
On a scale of 1 to 5, Bugbee placed the acreage and abundance of milfoil at Candlewood and Squantz this season at 2.5, far below last year’s rating of 4.5.
“The milfoil was nowhere near the proliferation and nuisance it was last year,” Bugbee said. “I wasn’t getting complaints about weeds this year like I normally do. Fishermen seemed to be happy.”
Bugbee suspects the improvement is owing largely to the thousands of sterile grass carp released in Candlewood over the past few years and Squantz this summer to feed on the milfoil.
He said he saw schools of grass carp in several coves while monitoring the lake, including Shelter Cove, Allens Cove, Brookfield Bay and to some extent Lattins Cove. He also saw coontail, a native aquatic plant that the carp avoid, covering the lakebed in the coves.
“This would tell us there’s a decent chance the grass carp are preferring the coves and feeding there,” Bugbee said.
Theodora Pinou, a Western Connecticut State University professor that led the study tracking the carp’s movements at Candlewood, said she too observed schools of carp in the coves.
“I do think the carp are helping, since some coves are much better and a high concentration of carp are being found there,” she said.
Forty-eight carp are fitted with tracking devices. Luke Mueller, one of two interns who assisted Pinou tracking them this summer, said they spotted four of the tracker-bearing fish in Shelter Cove.
“That just shows me that the fish are surviving and it’s a good indication for the program as a whole,” Mueller said last month. “Even the ones we didn’t find, they’re still around somewhere.”
Marsicano said the carp were generally found in the quieter coves where boat traffic is slow. He expects the carp will continue to play a larger role in management of the lake’s milfoil.
“As these coves have less and less milfoil, the carp will move out and find other places to eat,” he said. “They’re not going to starve.”
Marsicano also suspects a change in the annual winter drawdown of lakewater levels could have helped. Last year, FirstLight lowered the water earlier than it has in about 15 years, letting the plants dry out and exposing them to deadly cold before they could be insulated by ice or snow.
At Lake Lillinonah, by contrast, milfoil infestation was far worse in 2017 than in previous years.
For every acre of milfoil-infested water two years ago, Bugbee said, there were 10 acres this summer.
Greg Petriccione, chairman of the Lillinonah Lake Authority, said he suspects the presence of zebra mussels, another invasive species, might have contributed to the spread of the weeds this year.
The zebra mussels feed on organisms strained from the water, leaving the water clearer and allowing more sunlight to penetrate and help the milfoil grow, Petriccione said.
Homeowners also have also been cutting the milfoil without collecting the pieces, which are able to take root and grow, he said.
Petriccione said the authority is working with its advocacy group, Friends of the Lake, to create a milfoil management plan.
The difficulty of managing the lake is compounded by its position as part of the Housatonic River system.
“It’s a large lake and a large problem,” he said.
Len Greene, a spokesman for FirstLight Power Resources, which oversees several area lakes, including Lillinonah, said the company lacks the authority to create management plans or choose among treatment methods for water quality problems.
“We are however very supportive of the community’s efforts to eliminate the milfoil and we’ve funded several projects over the past year,” he said. “We’re very happy to say that we provided funding for both the Squantz Pond and Candlewood Lake grass carp programs, developed by the Town of New Fairfield and the Candlewood Lake Authority respectively.”
In the meantime, Petriccione said, homeowners can manage the milfoil independently, removing it by hand or machine or using benthic barriers — films or fabrics that keep plants from taking root in the lakebed.
“If you’re cutting, you have to be responsible and collect all of the cuttings or the problem will get worse,” he said. “It’s not recommended.”
firstname.lastname@example.org; 203-731-3345 (Newstimes Oct 7, 2017)