Last update: February 6, 2005 at 6:30 AM

Dennis Anderson: A curse of carp

Dennis Anderson,  Star Tribune

February 6, 2005 ANDY0206

Perhaps no bigger mistake has been made in fisheries management than the introduction in the late 1800s to the United States of carp.

Minnesotans -- and their state -- are still reeling from the planting here of a relatively few carp.

Like piscatorial mutants, carp are capable of living in waters that won't support many other finned species -- waters that are muddy, stagnant and warm.

Worse, because carp dig at lake and river bottoms with their noses, uprooting plants while seeking food, the carp stirs sediment into the water, clouding it and reducing light penetration.

In western Minnesota, high winds roil the region's many shallow lakes, continually resuspending the sediments. Lost, soon, is vegetation important to ducks and other wetland and shallow-lake wildlife.

The problem is so bad, said Department of Natural Resources wetland wildlife program leader Ray Norrgard, that, "Even if a shallow lake had everything else it needed to be productive for ducks, if it had carp, its benefits to waterfowl would be limited."

Fish stocking                                                                           Commercial carp

Minnesota Historical Society                                                   Minnesota Historical Society

Riches await settlers

When settlers arrived in Minnesota in the mid-1800s, many saw the state not only as fertile ground to plow -- but as a place to get rich.

The draining of wetlands began in earnest, paving the way -- almost literally -- for farming. Accompanying this was construction in the hinterlands of rail lines, usually over land gifted by the state and federal governments.

Railways were needed to move farmers' commodities to market, and to bring supplies to settlers. To Minnesota's earliest residents, everything seemed inexhaustibly abundant: Buffalo. Ducks. Prairie Chickens. Virgin timber. Clean water. And fish.

But the timber was soon cut and the buffalo shot off. Prairie chickens disappeared with the loss, to plows, of native grasses.

Attention quickly turned to the state's many lakes, not as places for relaxation and fishing in the manner suggested two centuries earlier by Izaak Walton -- but as profit centers.

And no state held more potential for commercial fish production than Minnesota.

"Situated as our state is ... we have the waters best adapted to the production of fish, in the largest quantity and the very best quality," said Minnesota's first State Fish Commissioners in their inaugural report dated 1875.

So Minnesota began, in earnest, its attempt to grow non-native fish. Atlantic salmon and "Shoodic" salmon were among the first species introduced, as well as lake trout, shad, bass and brook trout.

The native northern pike, meanwhile, was seen by the fish commissioners as "a calamity, and instead of propagating and protecting it, we are disposed to recommend that it be outlawed. We are fully convinced that every pickerel in the state simply occupies the room of a better fish, and the sooner he vacates our waters the better."

The state turns to carp

Most of the state's early attempts to stock game fish failed. Contrary to what the fish commission had hoped, for example, no salmon stocked in Minnesota swam the length of the Mississippi River to live in the Gulf of Mexico, before returning here to spawn.

But hope was not lost. The U.S. Fish Commission, under the direction of Spencer F. Baird, acquired 450 German (scaled) carp in 1877, with the fish arriving in the United States by steamer.

Baird's intent was to stock carp throughout the nation, and special rail tank cars were built to transport the fish westward from Washington, D.C.

Carp were "harmless in its relation to other fishes" and would provide food for settlers, particularly those of Eastern European descent, Baird believed.

"When all the conditions are favorable, the growth of the carp is almost incredible," said Milton Pierce in 1883, in a supplement published by the Minnesota State Fish Commission.

Money, more trouble

Some Minnesotans made money commercially harvesting carp and shipping the fish to markets back east. But many more residents wanted carp rid from state waters, and as early as 1909, the Minnesota Game and Fish Commission issued netting permits in attempts to eradicate carp.

Yet nearly a century later, carp are still here.

Worse, with more than 80 percent of wetlands drained from the state's southern and western farmlands, the relatively few lakes and rivers that remain in the area are subject to vastly altered hydrology.

During spring runoff, waters rise quickly, allowing carp to move from one river, lake or wetland to the next, virtually ensuring their continual dissemination.

What can be done?

The chance that duck populations can significantly recover in Minnesota without broad-based carp control, particularly in the western and southern parts of the state, is not good.

Where progress has occurred, shallow lakes have been sprayed with chemicals, killing all fish. Then barriers have been erected at the lake's inlets and outlets to prevent repopulation.

More promising, in the long term, are efforts to develop pheromones as a way to control fish populations. If these processes -- which perhaps are most aggressively being pursued in Australia -- can be developed, pheromones might be used to draw carp and other nuisance fish to traps. Sterilization of targeted male fish also is possible.

Among experts in this field is Peter Sorensen of the University of Minnesota.

Sources: Minnesota State Fish Commis-sion, First (1875) and Second (1876) Annual reports; "Carp and Carp Culture," (1883), Minnesota Fish Commission; St. Paul Pioneer Press, Aug. 4, 1910; "Without Careful Consideration, Why Carp Swim in Minnesota's Waters," by Steven R. Hoffbeck, Minnesota History magazine, summer 2001.