By: Neil Tolhurst
We’ve got trouble in “River City” and it’s not the kind of trouble that a boy’s band can solve. Our problem is biological: The Farmington River, one of our greatest local natural resources and tourist destinations, is in trouble and right now, there’s no way to solve that trouble.
A nasty, invasive organism has been found in the Farmington River. Its proper name is Didymosphenia geminata, commonly called didymo or “rock snot.” It is a diatom, a type of algae, with the capability of colonizing rivers and streams and starving the fish in them. The invasive potential of didymo can lead to covering the river and stream bottoms and interfering with the food chain for fish. This could be very serious for our popular fishing, kayaking, canoeing, tubing, swimming, and scenic Farmington River.
Didymo (New Zealand image)
According to the 2007 White Paper from the U.S. Environmental Protection Agency and the Federation of Fly Fishers*: “This diatom is able to dominate stream surfaces by covering up to 100% of substrate with thicknesses of greater than 20 cm (7.87 inches), greatly altering physical and biological conditions within streams. This species is expanding its geographic range in North America and the rate that nuisance blooms are reported by the public and local media are increasing.” The microscopic didymo organism blooms and produces stalks that extend outside of itself and attach to the rocks in a river or stream.
Connecticut’s Department of Environmental Protection included this in their 2011 Connecticut Angler’s Guide**: “This highly invasive freshwater alga (also called “rock snot”) has recently been found in several highly popular trout streams spread across the Northeast. Didymo has the potential to alter food webs and degrade habitat in many Connecticut trout streams.” Although that wording is cautious, didymo’s invasion and spread has the potential to destroy the fish population of the rivers and streams it invades. The Angler’s Guide also makes that point: “During blooms, didymo can produce large amounts of this stalk material, forming thick mats of cottony material that feels like wet wool on the bottoms of rivers and streams. These mats can potentially smother aquatic plants, mollusks, destroy invertebrate and fish habitat, and impact existing food webs.”
Scientists worldwide are working together with land managers, environmental agencies, local governments, local businesses, and fishing organizations to learn more about didymo and how to control it. Currently, there are limited options. A wallet-size card has been produced and distributed by the Candlewood Valley and Farmington Valley*** chapters of Trout Unlimited.**** The card presents three simple steps to stop the spread of didymo: Check, Clean, Dry. Details for each of these steps are on the card (see image); download a copy of this card: Didymo Alert (137). According to Bill Case, President of Farmington Valley Trout Unlimited, “I’ll be distributing the cards to UpCountry Sportfishing and other places where people who use the river can get them. We have other volunteers who will be helping get these out to everyone. It is really important to educate people about this. Fishermen have to be extremely careful with their boots, shoelaces, waders, flies, reels, rods, line, nets, and gravel guards to remove any traces of didymo so it won’t spread, particularly if they are fishing different areas that day.”
Grady Allen at UpCountry Sportfishing in New Hartford, pointed out that didymo “…can cling to the bottom and actually blanket an area. If it does that, then it is really bad. But in some situations it just invades in a small way and doesn’t cover the bottom. There are two ways to control it, not eliminate it. One is a water release for a dam-controlled river. That will dislodge it from the rocks and disperse it downriver to clear upriver sections. There are also chemical methods that wouldn’t be done unless absolutely necessary.”
Unfortunately, the Farmington River is particularly attractive to didymo invasion and growth as well as trout habitat. Bill Case explained, “Didymo likes cold water, rocky substrate, shallow areas, riffles, and it likes nutrient-poor rivers with relatively stable flow rates. The Farmington is cold and has a rocky bottom with less vegetation and plant nutrients than other rivers. It is also kept cold because of the bottom release from Hogback Dam that controls it. The trout also need consistently cold water temperatures.”
It is critical for all river users to recognize the need to follow the Check, Clean, Dry steps. They should be done whenever you leave the river to go to another place on the river or home. These are the only steps known at this time to help manage the trouble didymo can cause our beautiful Farmington River.
Websites referenced above:
* http://www.epa.gov/region8/water/didymosphenia/White%20Paper%20Jan%202007.pdf
**http://www.ct.gov/dep/lib/dep/fishing/anglers_guide/anguide.pdf
****http://www.tu.org/sites/www.tu.org/files/documents/tu_generalbrochure.pdf
Fishing along the banks of the Farmington River in New Hartford. Photo: NewHartfordPlus archives
