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

Abstract

The 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

Evaluation of Recently Implemented Harvest Regulations in a Data‐Limited Catfish Fishery with Bayesian Estimation

“…In turn, management scenario evaluations based on traditional estimation techniques are often limited to single gears or treat model outputs as deterministic point estimates (Dippold et al. 2016; Stewart et al. 2016; Moody‐Carpenter et al.…”

“…Investigating the potential for recruitment overfishing through spawning potential ratio or egg‐per‐recruit models may also be useful for future evaluation of length limit regulations for lower Ohio River catfishes (Slipke and Maceina 2001; Dippold et al. 2016; Stewart et al. 2016).…”

“…Yield‐per‐recruit analysis was performed using a formulation by Dippold et al. (2016) on a per‐1,000‐recruit basis, denoted asand…”

“…Therefore, we conducted YPR analysis under each scenario separately to determine the added benefit of the slot (with minimum and maximum lengths) compared to a simple minimum length limit. Yield-per-recruit analysis was performed using a formulation by Dippold et al (2016) on a per-1,000-recruit basis, denoted as…”

Using Harvest Slot Limits to Promote Stock Recovery and Broaden Age Structure in Marine Recreational Fisheries: A Case Study

“…Harvest slot limits have been implemented in limited marine commercial (Le Bris et al 2018) and marine recreational fisheries (Armstrong et al 1996; Pierce 2010; Powers et al 2012; ASMFC 2013; Muller et al 2015; Schmidtke et al 2017; FL FWCC 2019; MD DNR 2019; NYS DEC 2019; GMFMC 2020; WDFW 2019). In some marine recreational fisheries, harvest slots have been implemented and apparently not evaluated, whereas in others, harvest slot limits have been evaluated but not implemented (Leaf et al 2008; Dippold et al 2016; Morson et al 2017). These case studies, however, did not explicitly explore the effects of broadening age structure on the population.…”