Stewart, DR, JM Long, and DE Shoup. 2016. Simulation Modeling to Explore the Effects of Length-Based Harvest Regulations for Ictalurus Fisheries. North American Journal of Fisheries Management 36:1190-1204. DOI: 10.1080/02755947.2016.1204391
Abstract
Management of Blue Catfish Ictalurus furcatus and Channel Catfish I. punctatus for trophy production has
recently become more common. Typically, trophy management is attempted with length-based regulations that
allow for the moderate harvest of small fish but restrict the harvest of larger fish. However, the specific regulations
used vary considerably across populations, and no modeling efforts have evaluated their effectiveness. We used
simulation modeling to compare total yield, trophy biomass (Btrophy), and sustainability (spawning potential ratio
[SPR] > 0.30) of Blue Catfish and Channel Catfish populations under three scenarios: (1) current regulation
(typically a length-based trophy regulation), (2) the best-performing minimum length regulation (MLRbest), and
(3) the best-performing length-based trophy catfish regulation (LTRbest; “best performing” was defined as the
regulation that maximized yield, Btrophy, and sustainability). The Btrophy produced did not differ among the three
scenarios. For each fishery, the MLRbest and LTRbest produced greater yield (>22% more) than the current
regulation and maintained sustainability at higher finite exploitation rates (>0.30) than the current regulation.
The MLRbest and LTRbest produced similar yields and SPRs for Channel Catfish and similar yields for Blue Catfish;
however, the MLRbest for Blue Catfish produced more resilient fisheries (higher SPR) than the LTRbest. Overall, the
variation in yield, Btrophy, and SPR among populations was greater than the variation among regulations applied to
any given population, suggesting that population-specific regulations may be preferable to regulations applied to
geographic regions. We conclude that LTRs are useful for improving catfish yield and maintaining sustainability
without overly restricting harvest but are not effective at increasing the Btrophy of catfish.