Walleye wasteland to lots of smiles

I don’t always think of Vaughn Paragamian when I catch a walleye in one of Iowa’s interior rivers. Sometimes the action is just too fast and furious to think of anything but feeling the toink, setting the hook, landing the fish and getting my jig back in the zone.

But sometimes, when the bite cools, I offer a silent thank you to the fish detective who, in the late 1980s, figured out how to turn a walleye wasteland into a popular fishery.

As a research biologist in the 1970s and ’80s with the Iowa Department of Natural Resources, Paragamian devoted several years to understanding why the walleye, an Iowa native, could not sustain itself through natural reproduction in the state’s rivers and lakes.

Paragamian also demonstrated the futility of long-standing efforts to supplement poor natural reproduction of walleyes in interior rivers with fry stockings — a revelation that opened the door for fingerling stocking and the creation of a vibrant walleye fishery where none had existed.

In true detective fashion, Paragamian applied genetic analysis to demonstrate the futility of fry stockings in interior rivers. Paragamian and colleagues collected adult walleyes from the Cedar River and conducted genetic tests that showed just 19 percent of the captured fish were of the Spirit Lake strain — the strain that had been used in interior river fry stockings for 35 years.

In a 1988 article published in the Journal of the Iowa Academy of Science, Paragamian documented the study and wrote: “Stockings of walleye fry in interior rivers of Iowa is questionable and a more successful program should be designed.”

Paragamian said it took several years of “dogged effort” to convince DNR management to approve his proposal to raise walleye fingerlings in hatcheries and stock them in rivers after they had outgrown the need for zooplankton.

Another key component of the walleye success story, he said, is the expertise and effort of hatchery personnel, who have innovated practices, including the development of pelleted food, to produce the nearly 2 million fingerling walleyes stocked each year in Iowa.

DNR fisheries biologist Dan Kirby said walleye reproduction ranges from low to extremely low in Iowa’s interior rivers. The bottleneck, he said, is food for larval walleye.

Walleye fry depend on zooplankton for nourishment until they are big enough to eat aquatic insects and minnows. Unfortunately, during that critical window, Iowa’s interior rivers are generally high, swift, silt-laden and largely bereft of the life-sustaining food the fry need.

For the same reason that natural reproduction failed, a 35-year effort to stock millions of walleye fry also failed in interior rivers, though it succeeded in many of the state’s lakes and reservoirs.

So why can northern pike and smallmouth bass thrive without stocking in Iowa’s interior rivers? It comes down to timing, said fisheries research biologist Greg Gelwicks. Sufficient zooplankton is available for the fry of northern pike, which spawn earlier than walleye, and for the fry of smallmouth bass, which spawn later, he said. Northerns have the additional advantage of spawning in backwater, where more fry food is available than in main channels, where walleye typically spawn, Gelwicks said.

Kirby and Gelwicks said Iowa’s fingerling stocking program ranks among the DNR fisheries’ top success stories.

They said walleye fingerlings grow exceptionally fast in Iowa’s interior rivers, typically attaining lengths of 15 inches just 2½ years after stocking.

Kirby said fingerling survival rates peak when stocked in non-flooding rivers, which has been the case in each of the last three Junes.

“Going forward, walleye fishing is looking good,” he said.

After this spring’s highly successful collection season, DNR personnel are incubating 1,891 quarts of walleye eggs. In addition to the many millions of fry stocked in the state’s public waters, more than 1.6 million 2-inch fingerlings will be stocked in June into Iowa lakes and rivers and more than 320,000 6- to 9-inch fingerlings will be stocked in lakes later this fall.

After leaving Iowa in 1989, Paragamian conducted fruitful research during a 21-year career with Idaho Fish and Game. In a telephone interview Tuesday, he said he is pleased to be remembered as one of the architects of Iowa’s interior rivers walleye fishery.

“I’ve always considered my job to be putting smiles on the faces of anglers,” he said.