Marion Conover and Don Bonneau are two of the driving forces behind improvements to Iowa's fisheries. Photo by Rich Patterson.

Last May an excited middle-aged woman entered the Indian Creek Nature Center, where I work.

"I just caught a big fish," she said. "It doesn't have whiskers, so I know it's not a catfish, but I don't know what it is. Please tell me."

I walked with her down to Indian Creek and was delighted, but not surprised, to see a husky 4-pound walleye on her stringer. New to fishing, the woman was pleased that she had caught a premier game fish.

Her success wouldn't have been possible a half-century ago. For nearly three decades, two skilled biologists have worked to engineer improvements to the fishing in the Hawkeye State. Although not well known, they, along with the 91 Iowa fishery staff members they supervise, are responsible for the big walleye caught at the mouth of Indian Creek and many other success stories.

Marion Conover, the Iowa Department of Natural Resources' chief of fisheries, and Don Bonneau, who coordinates fisheries research for the agency, began their IDNR careers within a few months of each other in 1970, and so combine 72 years of experience in blending research and management to improve angling. Walleyes are one of the best examples.

"We knew walleye numbers in interior streams were very low, but we didn't know why," said Bonneau. "We had been stocking tiny walleyes by the hundreds of thousands, but it didn't improve populations of catchable fish. They just vanished somewhere in the river.

"We mounted several research projects and eventually learned that the tiny fish were either devoured by predators or died of other causes. This knowledge caused hatchery people and fishery managers to switch gears. We started raising walleyes to a larger size before releasing them. It worked: The newly stocked larger young walleyes were big and tough enough to avoid predators. They thrived, and today provide good fishing."

It wasn't as easy as Bonneau describes; a puzzle had to be solved first. Young walleyes are picky eaters that prefer live food, which makes raising them in quantity challenging in a hatchery situation. Feeding young fish a prepared dead ration is much more economical, but the feed used years ago had a problem: It sank. The fish ate it, but then sat on the bottom of hatchery ponds.