On a sunny September morning on the Connecticut River, Gregory Bugbee nudged his skiff into Selden Cove in Hadlyme and it happened again. He got stuck.

Two years ago, the cove was a magnet for anglers, a clear pond from which Selden Creek runs south through sunken meadows of wild rice and drowned oaks to join the river at the bottom of Selden Neck.

Now you can’t sink a hook in the cove. It can be difficult even to push a boat through. It is choked from its sandy bottom to the water’s surface by an acre-sized mat of a ferocious aquatic weed called hydrilla.

Hydrilla is a notoriously troublesome, invasive weed, particularly in the southern U.S., where it has clogged ponds and blocked rivers for years.

But what scientists have found in Selden Cove and everywhere else along the 200 miles of the Connecticut River and its tributaries below Springfield is something different: A previously undiscovered, genetically unique and exceptionally robust strain of hydrilla that so far has not been found anywhere else in the world.

The newly discovered Connecticut River strain has proven just as troubling as its southern relations, but is new enough to be something of a mystery. It was unknown two decades ago and has spread so explosively since that there is concern it could threaten the half century of environmental progress that has made the river a $1 billion-plus a year contributor to the state economy.

Marina owners have had to pay to have channels cleared. Kayakers can’t paddle through it, swimmers won’t swim in it and fishermen have given up on choice spots in coves and creeks. It has choked the shallow Mattabesset River in Middletown enough to slow the flow rate, threatening to turn it into a giant mosquito breeding ground. Owners of million dollar waterfront homes look out over mats of weed and tax collectors are worrying about property values.

Beyond aesthetics and recreation, there is reason to worry about the weed’s effect on the river ecosystem, not the least of which is its potential to threaten the big birds such as bald eagles and osprey that have repopulated the river. Similar, although genetically distinct, southern hydrilla harbors an algae-like cyanobacteria that produces a neurotoxin that gets into the food chain and kills birds. The new strain is being studied to learn whether it attracts the same bacteria.

Scientists like Bugbee, who is directing state efforts against hydrilla, are trying to figure out how to control Connecticut River hydrilla, the impact of which has been captured in a stunning video by the Connecticut Resource Conservation and Development Program, or CT RC&D.

There is fear it will crowd out long established plants and animals, sending an unpredictable ripple across the river ecosystem — just one of the new strain of hydrilla plants produces 191 tips that grow an inch a day. As important is finding a means of control — herbicide is one solution — that doesn’t hurt the river’s long term health.

...continued

©2023 Hartford Courant. Visit at courant.com. Distributed by Tribune Content Agency, LLC.