Evaluating Management Regimes using Per‐Recruit Models and Relative Stock Density for Mississippi's Spotted Seatrout

Abstract

AbstractThe Spotted Seatrout Cynoscion nebulosus is the most popular target of recreational inshore fisheries in Mississippi coastal waters. The Gulf of Mexico (GOM) stock of Spotted Seatrout is composed of spatially distinct substocks, and each state imposes unique bag and size limits. In Mississippi, the stock is managed using minimum length limits and daily bag limits. We used two methods to evaluate the efficacy of length restrictions and fishing mortality (F) levels: (1) a per‐recruit model simulation to evaluate the effects of proposed management actions on reproductive output and yield, and (2) an evaluation of how management regimes impact relative stock density (RSD). Relative stock density has been widely used as a management tool in recreational and generally freshwater fisheries but has not been widely employed in informing management of marine stocks. We used demographic information from fisheries‐independent sampling and length‐specific natural mortality estimates to construct both models. Our analysis suggested that decreased F, increased minimum length limits, and slot limits that include intermediate upper length limits could increase RSD measures for GOM Spotted Seatrout. We found that for all management regimes examined, local demographic properties of Spotted Seatrout may preclude large proportions of trophy‐length (≥686 mm TL) individuals. Per‐recruit modeling and RSD analysis are complementary approaches to inform management, as they consider spawning stock biomass, yield, and the maximization of angler satisfaction.Received October 6, 2015; accepted June 8, 2016 Published online September 13, 2016