Use of Length Limits to Reduce Variability in Crappie Fisheries

Abstract

Populations of crappie Pomoxis spp. usually exhibit considerable temporal variability in density and size structure and thereby pose problems for fishery management. We used an age-structured population model to explore whether length limits applied to recreational harvesting can reduce variability in crappie recruitment and adult density. Simulations showed that length limits did not reduce the magnitude of recruitment variability but did reduce fluctuations in adult population density. Our results suggest that fluctuations in crappie populations are not likely to be attenuated substantially by length limit restrictions because most of the variability stems from stochastic, density-independent recruitment. However, where recruitment variability is not excessive and stringent harvest regulations are practical, such restrictions can sustain high adult densities that cushion the effect of fluctuating recruitment on the ups and downs of the adult stock.