DNR crew finds some bass in silty Maquoketa

Biologists sampling fish stocks Monday below the failed Lake Delhi Dam were encouraged that they found adult smallmouth bass in the cloudy, silt-filled Maquoketa River, but they expressed concern about the future of what had been a world-class smallmouth bass fishery.

“My big concern for the next five years at least is how will the smallmouth bass reproduce and sustain themselves when silt covers much of the formerly rocky stream bed?” said Dan Kirby, the Department of Natural Resources fisheries biologist who led the fish survey crew.

The rocky substrate - which provides ideal smallmouth spawning areas and nurtures the crustaceans and aquatic insects that smallmouth rely on for food - has been largely covered with a 6-inch layer of squishy muck that had formed the bed of the lake drained when the dam failed on July 24.

In the first two months after the breach, 180,000 cubic yards of silt - the equivalent of 18,000 dump truck loads - washed into the Maquoketa River, according to Wayne Gieselman, the DNR's environmental services division administrator.

More than 70 days after the dam failure, the river remains opaque at a time of the year when its water would normally run clear.

“There's no reason to expect it to get any better as long as sediment keeps pouring in from the head cut” - the point at which the river carves itself a new channel through the thick layer of sediment that had been the bed of the former lake, Kirby said.

The DNR has been conducting annual fish counts in the 4.5-mile long black bass catch-and-release zone for the past 30 years, making it one of the state's most studied bodies of water. After additional testing today and Wednesday, Kirby will compare this year's data with that of previous years to quantify the impact of the dam breach on fish stocks.

On Monday, the census crew in its first five samples weighed and measured 47 channel catfish, 38 smallmouth bass, 13 largemouth bass, 12 walleyes and an assortment of panfish.

Among Kirby's initial impressions, without formal data comparisons, was that the number of catfish was inordinately large and that the smallmouth were inordinately mature.

Many of the catfish, which are more tolerant of cloudy water than bass and walleye, probably migrated from the lake into the area and appear to be healthy and well fed, Kirby said.

Almost all of the smallmouth were in the 12- to 17-inch range - mature fish that had been in the river several years. Younger specimens were almost totally absent from Monday's sampling.

“I saw more big smallmouth than I thought I would, but I wish I had seen more smaller ones. Reproduction and survival of small fish are going to be problems,” he said.

Kirby said he was not greatly surprised by the degradation of the fish habitat. “Too much silt and sand. You knew there was going to be trouble,” he said.

Fly fisherman Mike Jacobs of Monticello, who joined the DNR as a volunteer on Monday, said he came hoping for the best but expecting the worst.

After wading through many of his favorite fishing spots and finding the bottom covered with deep muck, he said the river lived up to his dire expectations.

At 54, Jacobs said he doubts he will live long enough to see the river return to its former splendor.