Mosel, K.J., D.A. Isermann, and J.F. Hansen. 2015. Evaluation of daily creel and minimum length limits for Black Crappies and Yellow Perch in Wisconsin. North American Journal of Fisheries Managment 35:1-13.
Abstract
Harvest regulations for Black Crappies Pomoxis nigromaculatus and Yellow Perch Perca flavescens fisheries in the northern USA and Canada have not been thoroughly evaluated and specific guidance regarding where minimum length limits (MLLs) might improve these fisheries is lacking. We determined if species-specific reductions in daily creel limits or MLLs could reduce harvest and improve yield and the mean total length (TL) of Yellow Perch and Black Crappies harvested by Wisconsin anglers. Harvest data from creel surveys indicated that most Wisconsin anglers did not harvest a Black Crappie (95%) or Yellow Perch (94%), and only a few anglers harvested a daily creel limit of 25 Yellow Perch (0.12%) or Black Crappies (0.04%). Daily creel limits would need to be ˂ 7 Black Crappies and ˂ 8 Yellow Perch per day to reduce harvest by 25% or more. Statewide MLLs would need to be ≥ 229-mm for Black Crappies and ≥ 203-mm for Yellow Perch to reduce harvest by 25% or more, but predicted responses to MLLs varied among simulated populations in relation to growth and mortality. In general, MLLs were not predicted to improve yield for these fisheries, but could improve mean TL of harvested fish. However, increases in mean TL of harvested fish ≥ 25 mm were only observed under 254- and 279-mm MLLs and our modeling suggested that anglers would have to accept large reductions in harvest (≥ 40%) to achieve these improvements. A 229-mm MLL offered a more equitable trade-off between improvements in the mean TL of harvested fish (11-21 mm improvements) and reductions in harvest (22-37% reductions). Our modeling results provide a framework for resource agencies to make more informed decisions regarding the implementation of harvest regulations for these fisheries, but information regarding angler preferences is needed for establishing appropriate management objectives and selecting harvest regulations.