Community Corner

Environmentalists Concerned About Discovery of Invasive Algae in Farmington River

'Rock Snot' found in West Branch of Farmington.

It’s nicknamed “rock snot” and it looks pretty much like you’d expect. And if you fish for trout in the West Branch of the Farmington River there is a good chance you will encounter it and maybe even carry it to other spots without knowing.

The state Department of Environmental Protection announced Tuesday that it has confirmed the presence of the invasive freshwater algae in the West Branch of the Farmington River.

Suspected clumps of the algae, didymosphenia geminataidymosphenia geminata, or “didymo,” were discovered by anglers in mid-March, according to the DEP. Last Friday, biologists at the Vermont Department of Environmental Conservation confirmed they were didymo, DEP officials said.

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“This find is very troubling,” DEP Deputy Commissioner Susan Frechette said in a press release. “Extensive blooms of this organism can harm the river ecosystem and decrease its recreational and economic value.”

DEP staff checked a number of sites along a seven-mile stretch of the West Branch in Hartland and Barkhamsted, Frechette said, and found clumps of didymo at all the  sites downstream of the Riverton Bridge. "Once didymo has spread, there’s no practical way to remove it from a river," she said.

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John Marona of Granby, an avid fly fisherman and former owner of a fly shop in Collinsville, said he is also troubled by the news. With the algae now in such a popular area, it’s likely it will be spread to other streams and rivers. 

“Now that it’s there, it’s going to difficult to keep it from spreading to other waters,” Marona said. 

Didymo is most common in cold, relatively shallow streams and rivers having a rocky bottom. Trout tend to thrive in such rivers as well.

The species can smother plants and insects, thereby affecting fish habitat. Since it can cling to boat hulls, felt soles on wading shoes and other materials, it is generally inadvertently spread by fishermen, canoestists, kayakers and others.

“It does alter the food web,” said Bill Foreman, an environmental analyst with the DEP’s Inland Fisheries Division.

Didymo (pronounced did-mo) is a single-cell organism that grows stalks that can stretch between 2 and 20 centimeters. These stalks can affect the amount of sunlight that hits the river bed, thereby affecting the life cycle of other organisms that rely on photosynthesis and, by extension, the overall ecosystem. This process is prolonged by the fact that the stalks are resistant to decomposition; they can outlive the actual cell by several months. 

In short, if certain aquatic species like mayflies and stoneflies are affected, fish like trout will not have the same amount of food, and the trout population could suffer, too. This was the case in a river in South Dakota, Foreman said. 

"If you were a mayfly or a stonefly you probably wouldn't be too happy about the change in habitat," Foreman said.

He said it’s hard to predict the algae’s effect on the Farmington River. "It could take 10 to 30 years to see what the impact of an invasive species is," he said.

In the meantime, the DEP's fishery division is working on a massive public education campaign to prevent the further spread of didymo. Signs are being designed to advise residents of the steps to prevent didymo from spreading, and they will be posted prominently near waterways.

The algae can affect the aesthetics of the river as well. During blooms, didymo takes on the form of wool-like mats that are generally gray, white or brown but not green.

Depending on the size of didymo blooms, the Farmington River may not be as attractive a location for these activities. Foreman said didymo looks a little like dried toilet paper. "It's unsightly," he said. 

The algae will affect all river users, Morona said. 

“We like that clean, pristine water,” he said. “If it doesn’t look like that it’s not as desirable for us all to use.” 

Foreman estimates that the Farmington River is the destination of choice for approximately 30,000 to 35,000 fishing trips each year. Ten percent of those are from out-of-state fishermen. "The Farmington River is probably a regionally known trout river," he said. "There are some really good trout streams" where didymo was found, he added.

The timing is somewhat ironic, too. The DEP will release its 2011 Angler's Guide next week and trout fishing season opens April 16.

The Farmington River is also popular for other recreational activities, such as canoeing, kayaking and tubing.

It’s futile for users to try to eradicate the algae since that will simply release more cells into the river, Foreman said.

Its cells are likely to spread downstream but it may not take as much hold in that area because the algae thrives in the cold, narrow, and rocky bottom habitat found in the Barkhamsted section. Downstream the river is wider, warmer and less rocky. 

Since the algae will not naturally spread upstream, Foreman also recommends that boaters and others not use the Barkhamsted section of the river and then go upstream in the same day.

The invasive species was first confirmed in the Northeast in 2007 and has spread to trout steams in New Hampshire, Vermont, New York, Pennsylvania, Maryland, West Virginia and Virginia

The DEP urges all river users to "check, clean and dry" by doing the following:

  • Check: Before leaving a river, stream or lake, remove all obvious clumps of algae and plant material from fishing gear, waders, clothing and footwear, canoes and kayaks, and anything else that has been in the water and look for hidden clumps. Leave them at the site. If you find any later, clean your gear and dispose of all material in the trash.
  • Clean: Soak/spray and scrub boats and all other “hard” items for at least one minute in either very hot (140°F) water, a 2 percent bleach solution, or a 5 percent dishwashing detergent solution. Absorbent materials such as clothes and felt soles on waders should be soaked for at least 40 minutes in very hot water (140°F), or 30 minutes in hot water (115°F) with 5 percent dishwashing detergent. Freezing thoroughly will also kill didymo.
  • Dry: If cleaning is not practical, after the item is completely dry to the touch, wait an additional 48 hours before contact or use in any other waterway.

To report possible sightings, call the DEP’s Inland Fisheries Division at 860-424-3474. More information on didymo and other aquatic nuisance species can be found at www.ct.gov/dep or or in the Connecticut Angler’s Guide (www.ct.gov/dep/lib/dep/fishing/anglers_guide/anguide.pdf).


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