OUTDOOR CORNER: WAPPAPELLO LAKE AVOIDS SLOT LIMITS

If you'll recall, last month we discussed several issues concerning fisheries management at Lake Girardeau. This month, I'll address the largest lake in Southeast Missouri, Wappapello Lake, where some anglers have requested new length limits on largemouth bass and crappie.

I'll try to address these issues with round two of 'Fact or Fiction'!

Fact or Fiction? A 12- to 15-inch slot limit on bass would improve the Wappapello Lake bass fishery.

Fiction! Slot length limits are used to allow harvest of abundant young bass, reducing the number of mouths to feed and allowing faster growth for the ones that remain. The present regulation (no size limit) already allows for the harvest of small bass, and a slot limit will not result in anything different.

A slot limit also protects the surviving bass that reach 12 inches until they grow to 15 inches, thus providing larger bass for the anglers. However, past angler surveys revealed that the majority of bass caught were being released and that harvest is low. If harvest is low, then length limits, such as a 12- to 15-inch slot limit, will have little, if any, effect on bass populations.

Fact or Fiction? Gizzard shad are the primary forage for bass and are the driving force to the status of these fisheries.

Fact! The major factor that affects the bass and crappie populations in Wappapello Lake is the number of small gizzard shad. Gizzard shad are the primary food for bass and crappie. Historically, annual gizzard shad production was inconsistent, usually providing an inadequate amount of prey for bass and crappie.

During the past 4-5 years, MDC has been working with the Corps of Engineers to improve gizzard shad spawning success through lake level management. A steady to slowly rising lake level during the spring when the water temperature is 65-75 degrees will encourage a longer, evenly distributed shad spawn. This new strategy has improved shad survival and abundance each year.

Fact or Fiction? White and black crappie populations have changed in recent years.

Fact! In the early 1990s, the majority (about 90-95%) of crappie in the lake were white crappie.

Growth was slow for both white and black crappie. Inconsistent and inadequate gizzard shad spawns were the major factor of the poor crappie growth. Interestingly, the increased number of shad in recent years has affected the white and black crappie differently.

White crappie growth has increased, but their numbers have not changed. Black crappie growth has remained slow, but they have increased in number.

At present, 68% of the crappie population are white crappie and 32% are black crappie. White crappie tend to grow larger than black crappie in the lake. In recent years, 11-28% of the white crappie were longer than 10 inches, while only 1% of the black crappie were longer than 10 inches. Few black crappie grow beyond 10 inches long because they grow slowly and die before they reach 10 inches, despite abundant forage.

Fact or Fiction? A 9- or 10-inch length limit on crappie should help the fishery.

Fiction! A 9- or 10-inch length limit would actually hurt the crappie fishery. The purpose of any minimum length limit is to protect small fish until they become larger. Length limits are used when either reproduction is limited or harvest of small fish is excessive. That is not the case at Wappapello Lake; plenty of small crappie are spawned each year and survive to harvestable size.

Each year we evaluate the white crappie population in Wappapello Lake with a standard assessment that is used statewide. In recent years, the population has been rated as either 'good' or 'excellent' indicating that a change in regulations is unnecessary. Furthermore, a minimum length limit would protect the majority of black crappie from harvest which could result in even more black crappie, which is not desired. Plus, black crappie would not be available for anglers to eat. Therefore, a minimum length limit would not benefit the crappie population.

Well, there you have it. How did you do with our little game of 'Fact or Fiction'. Hopefully this was fun and has helped inform you how and why we are managing Wappapello Lake.

Mark Boone is a fisheries management biologist with the Missouri Department of Conservation.