Norwalk River shows diverse fish population

In the shadow of Wilton Center, wildlife teems in the clear waters of the Norwalk River.

Just how much wildlife was the object of an effort to count fish by volunteers from Trout Unlimited and workers from the state Department of Energy and Environmental Protection on July 12. Nine men donned their waders, led by Trout Unlimited’s Jeff Yates and DEEP wild fish biologist Mike Humphreys, and made their way from the bridge near Ogden House to the bridge near Wilton River Park shopping plaza.

They were armed with electric wands and nets, ready to stun the fish and scoop them into a bucket, after which they would be identified, measured, and quickly release back in the river. The wands were connected to a car battery in a kayak that floated alongside the team and delivered a mild shock in the water. That caused the fish to become rigid and turn belly up, enabling them to be scooped up. They recovered quickly — as evidenced by the wriggling when Humphreys tried to measure them — and swam away as soon as returned to the water.

As the men got ready, Humphreys said he expected to find 13 species or more on the trip upstream.

“Diversity is a good indication” of the health of a river, Humphreys told The Bulletin. “Trout are a great indicator species.”

While there may be some non-native species in the river as well — such as the Asiatic clam that has been spotted — they don’t seem to be causing any obvious changes, he said.


The first 100 meters yielded American eel, rose-breasted sunfish, cutlip minnow, brown trout, cut nose dace and white sucker. Overall, there were nine species recorded.

“There are most certainly at least a few other species in the river that we did not find in our sample zone on Friday,” Humphreys said. “This is no cause for alarm. Some species are simply uncommon, transient pond species, or have patchy distribution.”

He added there were no “red flags” indicating the system was out of balance due to over-abundance of any one species.

The eels, Humphreys said, came all the way from the Sargasso Sea in the Atlantic Ocean. They have been in this area of the rive rin samples collected over the last 30 years, “however a substantial dam was removed a few years ago, and it appears that the number of eels at Schenks Island Park has increased as a result,” he said.

In the downstream parts of the river, where it runs straight and shallow, most of the fish caught were small, but upstream, where there are some deep pools, larger trout were netted, with the largest — a brown trout — measuring 37 centimeters, almost 15 inches.

Another brown trout measured 29 centimeters, which Humphreys estimated to be about two years old. A rainbow trout showed evidence of having escaped a bird attack, with a scar from a beak bite.

General impressions

“Like most rivers of this size in Connecticut, the Norwalk River has seen improved conditions in the past half century, due to increased environmental awareness, control of discharges, and habitat protection and enhancement,” Humphreys said when asked for his overall impressions.

“However challenges still remain. In particular, control of stormwater runoff containing a variety of contaminants, as well as natural habitat restoration in sections where the stream channel was altered historically offer promise for additional improvement. Also, a couple of significant dams remain, which increase stream temperatures and restrict fish movement.

“The fact that stocked trout fry can live and grow multiple years in the river, and reach a size desirable for fishermen to catch is strong evidence that the river is currently reasonably healthy. Continued attention to habitat restoration, dam removal, and water quality improvement should improve conditions even more in the future,” he said.

Yates was happy with the results of the count.

“I’m thrilled that in the last stretch, where we restored habitat in 2003, we caught about two dozen brown trout,” he said. “It shows the fish are using it.”

The restoration project that Trout Unlimited is planning for next month will create habitat not only for larger fish but also places for juvenile fish to grow. By excavating portions of the river to make it deeper, and positioning boulders and tree trunks in the river, the hope is the river will become more narrow and curvy with deep pools where fish can hide and spawn. It will also improve public access areas.

“We want the river to have a wide diversity,” he said.

One of the volunteers from Trout Unlimited on Friday was Bob Gault, a Wilton resident whose son Michael is on the Trout Ulimited board. Bob Gault has been fishing here since 1983. He said the fish counting was “a lot of fun. What better way to see what’s in the river?”

When asked about the restoration project he said, “I think everything they’re doing is fantastic. They are bringing the river back to to the way it was. The whole effort should be commended. It’s a prolific river.”