Evaluation of the effectiveness of a trophy Blue Catfish regulation in Oklahoma

Abstract

Growing interest in trophy Blue Catfish Ictalurus furcatus angling has resulted in implementation of trophy regulations by some natural resource agencies. On January 1, 2010, the Oklahoma Department of Wildlife Conservation adopted a regulation that only one Blue Catfish over 760 mm can be harvested per day to redirect angler harvest towards smaller fish, control harvest of large fish, and improve the overall size structure of these populations. This study evaluates whether the 762 mm length regulation has resulted in improved size structure of Blue Catfish in Oklahoma reservoirs. We compared pre- (2003-2006) and post- (2017-2018) regulation population parameters from seven Oklahoma reservoirs and found significant differences in length frequencies in all sampled reservoirs and age frequencies on the three reservoirs where otoliths were collected, although not necessarily congruent with expectations from the trophy regulation. Two lakes, for example Texoma and Ellsworth, exhibited significant increases in PSD, indicating a greater abundance of larger fish, but the other five lakes exhibited opposite or no clear trend. As of 2018, it appears the regulation change has been ineffective at meeting its stated goals, at least on a state-wide basis.