Crappie are notoriously cyclic. A lake is producing fair to good numbers of slabs for a couple years and then, mysteriously, the big fish disappear and are replaced with abundant but small fish. The opposite is also common after several years of catching all the paper-thin crappie you care to feed minnows to, big fish are again being caught.

In Part I, I explained how competition for food among abundant year classes results in slow growth, and how high size limits can increase the size of crappie available to anglers, but only if growth is fast and mortality is low.

The abundance of crappie in a year class is determined by the success of the spawn and survival during the first year. A good spawn and high survival results in a strong year class. Good recruitment — the production of young that survive their first winter — is necessary for strong crappie populations, but crappie populations often suffer from too much recruitment. Very high recruitment usually means slow growth and small fish for at least two or three years in Mississippi waters.

In Part II, I discussed how environmental conditions — density-independent factors like water levels and spring temperatures — largely determine the success of the spawn and year-class strength, but high densities of older and slower-growing crappie suppress high recruitment. Thus crappie cycles result from an interaction of environmental and density-dependent forces.

This final part will review some of the management strategies that have been tried to produce sustained, quality fisheries.

Reduce the abundance

Cyclic crappie populations have plagued managers for decades. The initial solution was liberal harvest regulations — no size limit and high creel limits. Sometimes crappie fisheries began producing more big fish after liberal harvest regulations were implemented. But, from what we know now, the transition to quality crappie fisheries probably had more to do with environmental conditions and adult crappie density than the liberal harvest.

There is one case where high harvest clearly improved the size of crappie available to anglers. Commercial fishermen were allowed to harvest crappie in Florida’s Lake Okeechobee. While it might take an army of recreational anglers to put a dent in a high-density, slow-growing crappie population, commercial fishermen fishing daily with nets and traps were able to reduce the crappie population and improve the growth rate — a successful but not very popular strategy.

Stocking predator fish to control crappie numbers has good potential. Stocked saugeye, a hatchery-produced hybrid between walleye and sauger and a highly valued sport fish, have improved the size structure of crappie populations in Oklahoma and South Dakota lakes. Saugeye likely can survive in Mississippi waters.

Saugeye, or possibly a different predator, may be a tool for improving crappie fisheries in Mississippi and elsewhere, but new predators should be very carefully evaluated before introduction. The first two questions to ask are, “how will it affect other fishes?” and “what will the introduced predator eat after it has reduced the young crappie?”

Increase recruitment

While much of the problem with crappie fisheries is slow growth of strong year classes, weak year classes occasionally are a problem. Stocking is the usual go-to solution when numbers need a boost, but survival generally is low when stocking into waters with established predator populations.

Crappie stocking contributed nothing to crappie fisheries in Lake Chicot, Ark. Crappie stocking had variable results in Tennessee, with stocked crappie contributing anywhere from nothing to up to 93 percent of a year class among different reservoirs. Factors affecting survival of stocked crappie warrant further evaluation.

Dr. Steve Miranda at Mississippi State is looking at a more natural solution to increasing crappie recruitment. Miranda and his students are evaluating the importance to crappie recruitment of natural backwaters at the uplake ends of Mississippi’s flood control reservoirs. Miranda reasons that these floodplain-like habitats that emulate natural crappie habitat in rivers can be important spawning habitat and provide the habitat and forage fish necessary for good survival and growth of young crappie. Pending the outcome of Miranda’s research, manipulation of reservoir water level may be used to improve and stabilize crappie recruitment.

Customized regulations

At this point in time, high length limits may hold the most promise for producing quality crappie fisheries. As discussed in Part I of this three-part series, high length limits only have the desired effects of increased yield of crappie when growth rate is fast and mortality is relatively low. High length limits, where and when they work, produce larger crappie. By restricting and delaying the harvest, high length limits also can prolong the quality-fish phase of the crappie cycles.

Length limits, however, have no beneficial effects when crappie are overabundant and growth is slow. Thus, strategies for controlling or preventing high recruitment and overabundant crappie are still needed. Also needed is a better understanding of factors that contribute to high natural mortality.

It is possible that customized regulations may be used to maintain the high density of adult crappie needed to suppress excessive recruitment and, at the same time, maintain the high growth rate needed for production of large crappie.

If it ain’t broke, don’t fix it

Mississippi’s Arc of Slabs — the four flood-control reservoirs in the Yazoo River basin — continue to produce quality crappie. MDWFP fisheries biologist Keith Meals, who oversees these lakes, attributes part of the crappie quality to the “huge sucking predator” — entrainment of crappie in the large volumes of water discharged from these lakes. While the loss of fish may be a gross misfortune for some fisheries, it may help keep the crappie densities low enough to maintain the fast growth needed to make the high length limits effective. The 12-inch/20 fish creel harvest regulations, in turn, help keep quality crappie in the fishery for several years. Nevertheless, angler harvest remains a concern in these recruitment-limited systems.

Ross Barnett Reservoir has been consistently producing good to excellent crappie fishing for the last few years. It is very likely that environmental conditions have been satisfactory for moderate to good recruitment, and the crappie have fast growth with fish reaching 9 inches in two years and 10 inches in three years. Despite the absence of high length limits and reduced creel limits, anglers are catching a lot of 10-inch fish. Possibly the adult crappie density is sufficient to keep recruitment in check.

Will the crappie fishing last? I asked Larry Bull, MDWFP fisheries biologist responsible for fisheries management on the Rez, what he foresaw for future crappie management on the big lake.

“I don’t foresee implementing high length limits unless something changes,” he said. “If it’s not broken, why would you want to try to fix it?”

Indeed, Barnett has the kind of fishery others try to produce with regulations.

Clearly, much remains to be learned about effective crappie management, but managers have come a long way from encouraging liberal harvest as a silver bullet for ailing crappie fisheries.