Walleye management

The walleye is native to most of Minnesota, flourishing in large, shallow, windswept lakes with gravel shoals, such as Mille Lacs, Leech, Winnibigoshish, Upper and Lower Red Lake, Lake of the Woods and Lake Vermilion. It is also native to many smaller lakes and streams in all of Minnesota's major drainages. Because of its popularity as a game and food fish, the walleye was introduced to many other lakes, where it has become established. The walleye now occupies about 1,700 lakes totalling 2 million acres and 100 warm-water streams totalling 3,000 miles.

Ecological types of Minnesota's waters.
Average number of hours needed to catch a walleye in Minnesota.

Habitat

The best way to maintain walleye numbers is to protect the variety of lakes and streams they inhabit through existing laws limiting pollution and regulating reservoir and tailrace water levels. Shoreland zoning and related laws aid walleye and other fish by controlling lake and river shoreline development and protecting aquatic plants that walleye or forage fish use for cover. It is particularly important to protect rocky spawning shoals from pollution and sedimentation.

Sometimes, walleye spawning areas can be enlarged or rehabilitated by trucking loads of carefully selected boulders and cobble over the ice and dropping it at a precise location over the spawning area. Warm weather melts the ice and deposits the substrate. However, these artificial spawning reefs have their limits. Imagine the amount of rock that would have to be hauled onto Mille Lacs to add significantly to the thousands of acres of natural spawning habitat.

The water level of large reservoirs can be manipulated to increase walleye reproduction. Low water during much of the year allows waves to crash over rocky reefs and shallows, clearing sediment from spawning areas. By raising the water level during early spring, as would happen under natural conditions, reservoir manager cover these reefs with water of adequate depth for the walleye to spawn.

On most waters, closed seasons protect walleye during spawning. Possession limits distribute the total catch among many anglers. Lately, fish managers have been looking at special regulations as a way to protect walleye.

For many years fish managers operated under the principle of maximum sustained yield. Their goal was to provide to anglers year after year the greatest possible poundage of desirable fish - either as a few lunkers or as many small walleye.

Managed in this way, Minnesota's large lakes have yielded to anglers millions of walleye every year. In total weight of walleye, our lakes are as productive as ever. But anglers have complained that the fish are getting smaller.

Several things may be at the root of this. Modern walleye fishing techniques are perhaps better at catching medium-sized fish than large fish. Also, a strong year-class can dominate the walleye population; when these abundant fish are small, it will appear as though the lake is filled with nothing but small fish. Then, as these abundant fish grow larger, the angler will begin catching large fish.

Nonetheless, evidence suggests that the average size of walleye in the creel from the large walleye lakes is indeed declining - not because of some temporary aberration, but over the long term. In Winnibigoshish, for example, fishing pressure increased more than 700 percent from 1939 to 1977 while walleye yields (in pounds per acre) increased 150 percent. Most dramatically, however, the average weight of walleye that were kept declined from 2.2 pounds in 1939 to 1.3 pounds in the 1950's to 1.1 pounds in the 1970's. If Winnibigoshish is any indication, the average angler is catching fewer and smaller walleye. The problem apparently stems from fishing pressure.

Not only are more anglers spending more time at their sport, they also are better educated in their fishing techniques and better outfitted. This intense fishing pressure is like a mower blade, chopping off the seed and blossom and leaving the stubble - in this case the small walleye that proliferate to fill the void left by the larger fish. As the average size of the fish drops, anglers are willing to keep smaller and smaller fish, and the problem of fishing pressure is compounded.

While our lakes produce as many pounds of fish as ever, anglers have noticed that each is catching fewer fish (because they're sharing the yield with other anglers) and that these fish are smaller. As each person's catch declines in number and size of fish, the old management philosophy of maximum sustained yield - large fish or small - comes increasingly under attack.

What's the solution?

Anglers want more large fish. However, raising and releasing lunkers is prohibitively expensive.

If we can't add large fish, we have one option: we can TAKE fewer large fish.

Ways of limiting the take include shortening the season and outlawing depthfinders and other sophisticated equipment. These measures would be unpopular. The DNR would prefer to limit directly the number of fish kept rather than to cut down on the amount of time anglers spend on the water or to dictate the equipment they can use.

Many fishing groups have suggested that anglers practice more "catch-and-release" fishing and that the DNR institute size limits to protect large fish.

When complaints erupted about poor fishing on Mille Lacs, the DNR and local anglers group developed just such a plan. Early-season night fishing was closed to limit the take when fishing pressure was greatest and walleye were most vulnerable. A new size limit allowed anglers a daily bag of only one fish longer than 20 inches to protect large fish and put more pressure on small fish.

The Mille Lacs regulations are unusual in that they apply only to Mille Lacs. They do not affect the statewide seasons and limits. Thus, they are called "special regulations." Special regulations are tailored to characteristics of the fish population, fishing pressure and other problems unique to a single lake or river. They may also be designed for a particular goal. Thus, one lake may be managed to produce a few trophy fish while another may be managed to produce many smaller fish for the frying pan.

Though the DNR is just beginning to experiment with special regulations for walleye, it appears likely they will become increasingly important.

One kind of special regulation that has been used with other species and may be useful in walleye management is the "slot" limit, which protects a certain size fish. For example, anglers may be required to return all fish between 18 and 22 inches but can keep fish outside that slot. The slot limit would allow anglers to keep "eating-sized" fish as well as a few trophies. Medium-sized fish would be protected to make for better fishing (not to protect brood stock, which usually exists in sufficient numbers). The number of small fish would be reduced through angling pressure and cannibalism by large walleye. Often, growth rates improve as the small fish become fewer, and the number of large fish increases in this way as well. The secret lies in finding the proper slot for the productivity of the lake and the growth rates of the walleye in it. Success depends on good survey data.

What about the familiar minimum-size limit? For example, a regulation may require that all fish under 12 inches be returned to the water. That way, the little ones will have a chance to grow to be big ones, right? Well, no. They'll have the chance to grow to about 113/4 inches and then likely will be yanked from the lake. A minimum-size limit will produce big walleye only if it is pushed up to lunker size--22 inches, for example. That kind of restriction is nearly catch-and-release requirement.

Though size restrictions have been a hot topic, there are other ways to limit the kill and improve fishing.

One way is to greatly reduce the possession limit - perhaps from 6 to 1 - and thus encourage catch-and-release fishing.

Stocking

Minnesota's cool-water hatcheries and rearing ponds each year produce 2 million to 5 million walleye fingerlings and millions of fry. The major value is to provide walleye fishing in areas of the state void of natural walleye populations. Over the years, the mixture of ever-increasing walleye mania and the lure of tourism bucks has produced an over-reliance on stocking. As a result of this emphasis on hatchery production, many anglers wrongly believed that stocking was a panacea for poor fishing, that any lake could be a walleye lake, and that the walleye could not thrive without artificial propagation.

None of that is true. Simply put, stocking a lot of small fish does not guarantee catching a lot of big fish. Furthermore, native Minnesota walleye have flourished since the Ice Age without our help. But having relied on the stocking program for several decades, the DNR has found it difficult to convince anglers of other effective management tools.

Still, the effect on the state's total fishery is limited. One fish manager estimated that perhaps only 5 percent of the walleye that anglers catch come from a hatchery. The rest were the result of natural reproduction. "We survive on Mother Nature's bounty," he said, "which is a heck of a lot cheaper than stocking fish."

In the words of one DNR report: "There is no evidence that the walleye population of the stocked natural walleye lakes sampled were increased over that which might occur naturally without stocking." The point is this: Given the great cost of raising walleye, why put them in lakes where walleye already spawn successfully or where stocked walleye do not improve fishing?

There is evidence that stocking can be harmful as well. Stocked walleye may compete for food with other game fish, particularly largemouth or smallmouth bass. The result may be fewer or smaller bass. And because the bass is a more efficient predator of small sunfish than the walleye (which feeds more on perch), the introduction of walleye may contribute to stunting of the panfish. These are all issues that are just now being studied. It seems, however, that stocking is not the benign activity it once was assumed to be.

Despite its limitations, stocking is a useful tool for some purposes:

  • Walleye are introduced to lakes that have been "rehabilitated" (that is, where the previous fish were deemed undesirable and removed). Where habitat is suitable, these introductions often establish self-sustaining fisheries.
  • In one of the most popular and effective uses of stocking, walleye fry are put in heavily used lakes that occasionally winter-kill. These lakes - many of them in southern Minnesota - are fertile, and walleye fry quickly grow into "keepers." The fish may be given some protection with aerators to increase winter oxygen, but still, stocking these lakes is a gamble. The risk is losing great numbers of game fish before they can be caught. The payoff is desirable game fish where otherwise nongame fish would swim. Heavy use by anglers makes the gamble worth taking.
  • Walleye are also stocked in lakes with all the elements necessary for survival except suitable spawning areas. This approach works in lakes that once were natural walleye producers but that since have succumbed to farm runoff and lakeshore development. As fertilizers, septic-tank seepages and other sources of nutrients have enriched waters, algae proliferate and smother walleye eggs. In this instance, stocking is a prosthesis for an injured body of water.

Occasionally, walleye are stocked to bolster the number of catchable fish where heavy use or poor reproduction justifies the expense. This is extremely expensive, however. Only occasionally is it a good investment.

The future

Loss of habitat and increasing fishing pressure will continue to be the biggest issues in walleye management.

If walleye are to have good areas to spawn and grow, regulations must prevent water pollution, control agricultural runoff, restrict lakeshore development, and control the clearing of aquatic vegetation. If habitat can be protected, anglers and fish managers still must contend with fishing pressure. As more people fish more effectively on the state's big walleye lakes, they will have two choices:

  • Put up with reduced quality of walleye fishing, or
  • Reduce the kill of desirable fish through catch-and-release fishing, size limits, preference for other species, or other methods that limit the walleye catch. Some lakes may be managed for trophies; others for many pan-sized fish. Anglers may find first-rate walleye fishing on lesser-known streams and small lakes.

Walleye stocking, that popularly imagined panacea, is a useful tool in correcting problems and maintaining fisheries in special circumstances on a modest scale. But as medicine for walleye fishing statewide, it isn't the answer.