The Fishing Wire (www.thefishingwire.com) published a report concerning crappie fishing research in Florida. The following are highlights of the report.
Biologists with the FWC’s Fish and Wildlife Research Institute (FWRI) and Division of Freshwater Fisheries Management (DFFM) are often stopped and asked questions.
What do crappie regulations accomplish? Different water bodies can be managed for different goals. For example, Lake Jackson is designed to produce very large (trophy) crappie. A different size limit at Lake Griffin was implemented to increase the total weight angler’s harvest by increasing the size of the fish they take home. Regulations are simply designed to help sustain the crappie fishery.
How do length limits work? By putting fish back anglers keep the total number of fish up. It also gives released fish more time to grow and a chance to reproduce.
Why don’t length limits work the same on all lakes? Studies in several states have revealed length limits succeed in producing bigger fish or higher total catch by weight if: fish growth is fast; natural mortality is low; and fishing pressure is high. If growth is slow, fish may not grow to legal size.
What kinds of data do biologists collect? When a length limit is proposed, biologists need to find out three things: growth rates, mortality and angler effort and harvest.
For growth rates the biologists must know how big fish are at any given age. Information is from carcasses of angler-harvested crappie. They learn how fast fish grow, at what age they reach the proposed minimum size limit and what size fish anglers tend to keep.
Mortality (Death Rates) are estimated by analyzing the proportion of fish in each age group in the harvest. To separate natural deaths from angler harvests, biologists collect live fish and mark them with reward tags.
Angler Effort and Harvest are assessed by using creek (angler) surveys. In these surveys, biologists count the anglers on the lake and politely approach boats to find out start time, targeted species, number of fish caught and number of fish harvested.
Summary. After everything has been collected, biologists put the data into models to estimate how the fishery might change under different regulations. Once a regulation takes effect, biologists continue to monitor the population and conduct creel surveys to gauge angler satisfaction and record the number and size of fish are being harvested.
