March 2008 OutdoorIllinois / 19

An insider’s look at the anatomy of proposed fishingregulation changes at Lake Shelbyville.

NewCrappieRegsfor ShelbyvilleStory and Photos ByMike Mounce

Advancements in fish-eries management haveled to a greater under-standing of how fishingregulations function.

Where appropriate, biologists can nowtailor regulations to the variable popula-tion dynamics of individual species inspecific lakes. Changes in fish popula-tion structure and fishing quality usual-ly result in a biologists’ review of cur-rent regulations or the need for newregulations. Because of crappie’simproved status as a sportfish, harvestregulations for crappie have becomeincreasingly popular.Minimum length limits, usually 9- or

10-inch size limits, coupled withreduced creel limits, have been widelyapplied to improve crappie harvest andfishing quality nationwide. Minimumlength limits have predictable effectsfor all species, including crappie, usual-ly resulting in increased catch rates, butalso a reduction of overall harvest,which is not ideal. In lakes where thesurvival of crappie fry (recruitment) ispoor and growth rates are fast, mini-mum length limits are effective. Ifrecruitment is moderate to good andgrowth rates average to slow, protec-tion under a minimum length limit willresult in crappie “stacking up” or“stunting” just under the size limit.Crappie recruitment in many waterbodies often is highly variable, makingthe application of appropriate limits dif-ficult over long periods of time.Since the late 1980s, crappie harvest

on Lake Shelbyville has been regulated

by a 9-inch, and more recently a 10-inch, minimum length limit andreduced creel limit. Crappie recruit-ment in the lake has been highly vari-

able, but on average has improved overrecent years, especially for black crap-pie. Analysis of crappie age and growthin spring 2007 indicates the growthrates of all ages of black crappie werebelow state averages. However, whitecrappie growth rates were higher thanthe state average for young fish, but

Crappie anglers and fishing guides

were involved in development of

new Lake Shelbyville regulations.

20 / OutdoorIllinois March 2008

slower than the state average for whitecrappie age 4 and older. Given thisinformation, the current regulation maynot be providing the best results forthis fishery.While a few anglers have reported

good fishing results for legal-size crap-pie on Lake Shelbyville over the pastseveral years, the majority of anglershave been catching high numbers ofcrappie just below the size limit, butrelatively few over the current lengthlimit. This has resulted in frustratedanglers and a reduction in the numberof fishermen visiting Lake Shelbyville.Since fishing is the most popular recre-ational activity on the lake, the loss ofanglers can have a significant effect onthe local economy.Because of the social and economic

importance of the crappie fishery ofLake Shelbyville, a new harvest regula-tion was considered for crappie inspring 2007. Eight regulations or com-binations of regulations were evaluatedon their merit to help improve crappiesize structure on Lake Shelbyville. Ameeting was held to discuss these regu-lations among crappie fishermen, fish-ing guides, and state and federal offi-

cials. Due to crappie population dynam-ics and the dynamics of fishing activityafter implementation of a new regula-tion, one alternative regulation wasdetermined to likely produce the bestresults over the longest period of time.In summer 2007, the most practical

regulation was presented to, andapproved by, the Department of Natur-al Resources’ Division of Fisheries Man-agement Review Committee. The newregulation—a little different than what

anglers are accustomed to seeing in theMidwest—allows for the continued har-vest of 10 crappie that are 10 inches orlarger but also allows the harvest of fivecrappie less than 10 inches. The goal isto thin the number of crappie under 10inches slightly, providing the gentlenudge necessary to improve growth,recruitment and fishing quality.The limit below 10 inches was set at

only five fish to prevent potential overharvest of “9-inch” white crappie. Creelsurveys found white crappie—about9:1 ratio of white to black crappie—make up the bulk of the crappiescaught and harvested. In addition,because a large majority of the whitecrappie caught by anglers have beenbetween 9.5 and 10 inches, only aslight boost in growth rates is anticipat-ed to improve size structure.The new regulation will take effect

on April 1, 2008. In time, it shouldimprove angling quality and satisfac-tion, and maintain—for an extendedperiod of time—a more desirable bal-ance of crappie both shorter and longerthan 10 inches.Improved fishing quality and satisfac-

tion will benefit local fishermen andshould attract additional fishermenfrom outside the immediate area. Theadditional tourism generated by a high-quality fishery will provide a significantboost to the local economy as well,benefitting fishermen and non-fisher-men alike.

Mike Mounce is the DNR fisheries biolo-

gist based in Charleston.

A nglers are reminded that “culling”fish (replacing a kept fish with

larger fish caught later) is illegal unlessthey are in a bonafide fishing tourna-ment. Due to the wide publicity oftournament fishing, where culling islegal, many anglers do not realize thatthis activity is illegal for recreational(non-tournament) fishermen. Illegalculling was one of the many factorsconsidered when deciding the mostappropriate crappie regulation for LakeShelbyville. Even in the best condi-tions, fish kept for any length of timeand later released will suffer some mor-tality due to extra handling, whichadds to the angling mortality of fishpopulations and is detrimental to thelong-term quality of fishing. Death fromculling is usually delayed and oftenfishermen are unaware of the conse-quences. For the benefit of theresource, the decision to keep orrelease a fish should be made immedi-ately—and adhered to.

New Lake Shelbyville regulations

take into account different growth

rates for black (left) and white

(above) crappie.