Maquoketa River providing plenty of treats

DELHI — Most butterflies of my acquaintance avoid people, but not the hackberry imperial.

During a Father’s Day float trip on the Maquoketa River, I counted 13 at one time on the hat of my friend Mike Jacobs of Monticello.

They were so numerous they had to land anywhere they could, including on top of each other and on a film of foam and cottonwood fluff that collected on the surface of an eddy.

Mike, an experienced and ever alert fly fisherman, noticed something unseen was slurping them off the scum. While his Styrofoam popper did not precisely match the hatch, it worked well enough for Mike to say he’d caught his first smallmouth bass on a butterfly imitation.

Moments later, as I was retrieving a topwater lure through a midstream eddy, I witnessed a scene that still seems like a dream or hallucination.

With all the suddenness of a missile launch, a smallmouth bass erupted from the stream to attack the mini-buzz bait, and a nanosecond later, another dozen foot-long bass rose skittering to the surface like a school of minnows and disappeared as abruptly when they saw me looming over them.

Mike confirmed he’d seen what I thought I saw.

By noon we’d caught and released more than 50 fish — mostly smallmouth (many in the 12-to-15-inch range) along with a few largemouth, crappies and bluegills and one walleye.

But excitement peaked on two occasions when large fish refused to be caught. Mike played what we presumed to be a giant carp for several minutes before it broke his line on an irresistible downstream surge without ever having shown itself. A bass that would have been the “fish of the day” later broke Mike’s line as he tried to steer it away from an underwater log.

As we neared the end of our run, eating lunch in one of the few shady spots at high noon on a blue sky day, we marveled at the river’s recovery from the catastrophic silt inundation that followed the 2010 failure of the Lake Delhi dam.

Eighty years’ accumulation of lakebed mud and sand flowed downstream, burying the rocky stream bed, which for generations had nurtured the state's foremost smallmouth bass fishery in a 4.5-mile-long, bluff-walled gorge below the dam.

At the time Mike and I believed we would not live long enough to see the Maquoketa River catch-and-release zone regain its status as a world-class stream fishery for smallmouth bass. But time and the river have carried off the stifling sediment; years of good natural reproduction have strengthened the game fish population; and the award-winning, innovative spillway on the new Lake Delhi dam assures a near-continuous downstream flow of clear water.

The state’s run of the river rule requires water to be released downstream at the same rate it enters the lake from above. That flow is maintained for about 300 days a year over the accordion-shaped labyrinth spillway, said Lake Delhi resident Pat Colgan, a retired hydroelectric engineer. In effect, the downstream flow generally consists of clean water at the lake’s surface, rather than the murkier lake-bottom water released through flood gates, he said.

Asked if the catch-and-release zone has fully recovered, Dan Kirby, the Department of Natural Resources fisheries biologist who manages the Maquoketa, said: “We are getting there. It’s close.”

The big bass — the 18-to-20 inchers — still are not as plentiful as they were before 2010, Kirby said.

But the river is full of candidates to take their place.