Building Iowa fish 'Field of Dreams'

Thursday, May 15, 2008

No one who has ever seen Field of Dreams can forget the signature line from that motion picture: "Build it and they will come."

What if the scenario of a mythic Iowa cornfield was changed just a bit: no ball diamonds, but fishing lakes amidst fields of Iowa corn? And what if the fabled legend to emerge from another era was a fish, one that's particular about its need for clear, clean water?

The fish is the walleye. The State is Iowa. And the tale is completely true.

Walleye are tremendously popular with anglers, but they are not the easiest fish to raise in a hatchery. In fact, they present some very unique and difficult challenges.

The Iowa DNR began a comprehensive effort to improve its walleye fisheries more than 25 years ago. According to Marion Conover, Fisheries bureau chief, surveys showed that walleye were among the most sought-after sport fish by anglers. Yet, the species enjoyed only limited natural reproduction in Iowa.

"Many Iowans may not realize the science and research behind the great walleye fishing we now have in Iowa," said Conover. "It's a fascinating process of understanding the biology of fish survival and growth."

While DNR researchers have been able to demonstrate that stocking walleye fry - newly hatched fish - can survive and grow to an angler-acceptable size, stocking larger fish in lakes like Storm Lake improves the odds.

One method pioneered by Iowa involves transferring walleye fry from hatchery ponds to tanks in dark rooms, where they are trained to accept a specially formulated high-protein pellet feed.

"The darkened room reduces stress on the young fish, which in turn increases acceptance of the new diet and growth of the small fish," said Conover. As a result, Iowa enjoys unusually high survival rates - 85 percent this past year, an almost unheard of achievement when compared to other methods.

The DNR has been able to show, quite compellingly, that improved water quality not only yields better angling success, but contributes dramatically to increased outdoor recreational use. One Iowa state park, Lake Ahquabi in Warren County, saw its visitation figures grow tenfold, from 60,000 visits per year to 600,000, due to its dramatically improved water quality and recreational fishing.

Northwest Iowa lakes benefiting from the walleye research program include Storm Lake, Black Hawk Lake, Brushy Creek, West Okoboji, DeSoto Bend and Clear Lake, all of which are now prime walleye fishing venues thanks to stocking efforts.

The walleye work carried out in Iowa was made possible by the sales of Iowa fishing licenses and by tfederal excise tax monies collected on fishing tackle and motorboat fuel.

"Every time an Iowa angler buys a license or purchases fishing gear or boat fuel, they are making a real difference to Iowa's lakes and fish," said Conover.

The DNR's groundbreaking work will have valuable applications well beyond the Hawkeye State, as other states learn from Iowa's example, proving once again that "if you build it they will come."

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