GMF leads bug count to determine stream health

FALLS VILLAGE — One way to determine if a stream has trout in it is to fish it, either with rod and reel, or by electrofishing, in which a section is zapped with electricity and stunned fish float to the surface, where they can be quickly cataloged before they get their wits back and swim away.

The other way is to look at the local environment. Trout need cold, clear, oxygenated water, and they need bugs to eat. If these conditions are met, then the habitat probably supports trout.

This was the plan along Wangum Brook in Great Mountain Forest on the Falls Village side on Saturday, May 31.

Educator Tom Fahsbender met at the GMF barn on Canaan Mountain Road with a group of adults and high school students for a quick briefing at 9 a.m.

He explained that he had performed the same survey in the same spot about 10 years ago with a different group of volunteers.

The work is part of a state Department of Energy and Environmental Protection program called Riffle Bioassessment by Volunteers.

The surveys, conducted by similar groups of volunteers statewide, look for streams and rivers with no known pollution sensitivities, a year-round flow, plenty of riffles, no dams, and relatively shallow so the volunteers can get in and out without too much trouble.

Fahsbender said he will submit the information gathered by the group to DEEP, which will include it in the next update of the health of the state’s streams.

Of particular interest were macroinvertebrates, such as may flies, caddis flies, stone flies and dobson flies — also known as hellgrammites.

Fahsbender said the presence of these insects is used as “a proxy for water quality.”

“If it’s too warm or polluted or not oxygenated, these organisms won’t live there.”

“You don’t have to be a scientist,” he emphasized.

“It all comes from fly-fishing,” he added. Fly anglers know about the different insects that make up a trout’s diet, and use artificial imitations of real bugs to catch trout.

The surveys must be done the same way, with the same equipment. Fahsbender brandished a kick net with a rectangular business end of 18 x 14 inches and a fine mesh net.

As a bonus, the handle end serves as a wading staff as the volunteer enters the often slippery stream.

The procedure went like this.Each team — there were two teams of two people and one team of three on this occasion — selected a riffle and two areas within the riffle to sample.

Prior to entering the stream each team got about an inch of water into a smallish plastic storage bin and stashed it securely along the bank.

Once in the stream, one person held the net steady in the flow while the other spent two minutes just upstream of the net, picking up rocks and scrubbing them with their hands.

Cali Hoehne held the net steady while her mother Keri scrubbed insects off rocks.Patrick L. Sullivan

Fahsbender said this is necessary to dislodge the insects, which often cling quite stubbornly to the rocks.The sampler spent a minute stirring the streambed with a foot to dislodge anything that might have escaped the first procedure.

Then the gunk in the net was carefully emptied into the storage bin.

Just to make everything more exciting, it rained off and on during the collection period. And young Jackson Davis lost the felt sole from one of his hip boots.

The somewhat soggy crew then drove back up the hill to the GMF barn to examine their samples.

As expected, this involved a lot of separating stream matter — leaves, moss — and bugs. Sometimes a bug was lurking in the stream matter.

Bugs were then transferred into ice cube trays with a bit of water to keep them happy.

Kurt and Jonas Johnson from North Canaan — and Housatonic Valley Regional High School — found a prize: a cased caddis fly.

“It was coming out when we found it but it went back in” observed Jonas.

Jackson Davis, his mother Barb, and Julia Reinert nabbed a stonefly. The Davises are from Canton and Reinert from Winsted. The teens, along with a member of team number three, Cali Hoehne of Torrington, are in the agriculture education program at Northwestern Regional High School.

Cali’s mother Keri rounded out the third team. She displayed considerable rock-scrubbing skills.

Fahsbender scooted around the room, keeping an eye on things and reacting to the occasional cries of triumph. It was a pleasant scene.

For more information on the RBV program, see portal.ct.gov/deep/water/inland-water-monitoring/riffle-bioassessment-by-volunteers-rbv