Simulation Modeling to Explore the Effects of Length-Based Harvest Regulations for Ictalurus Fisheries.

Management of Blue CatfishIctalurus furcatusand Channel CatfishI. punctatusfor 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). TheBtrophyproduced did not differ among the three scenarios. For each fishery, the MLRbestand LTRbestproduced greater yield (>22% more) than the current regulation and maintained sustainability at higher finite exploitation rates (>0.30) than the current regulation. The MLRbestand LTRbestproduced similar yields and SPRs for Channel Catfish and similar yields for Blue Catfish; however, the MLRbestfor 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 theBtrophyof catfish. Received February 1, 2016; accepted June 16, 2016 [ABSTRACT FROM AUTHOR]