Add to my Schedule 201C Nov 28, 2018 Oral Abstracts
Living Resources 09:30 AM - 09:45 AM

Assessment of stocks such as Blue Crab (Callinectes sapidus) in the northern Gulf of Mexico (nGOM) are challenging, partly, because age-structured approaches cannot be used. To overcome model limitations and data availability challenges, we constructed a surplus production model for the gulf-wide stock, evaluated in a Hierarchical Bayesian (HB) framework. The objectives of this study were to develop a HB surplus production model for assessing the nGOM Blue Crab stock and evaluate the sensitivity of the model to the inclusion of fishery-independent indices of abundance (IOA). The HB approach allows the inclusion of prior information and the designation of regional hyperparameters to facilitate estimation of parameters and explicitly model uncertainty. We used commercial harvests and fishery-independent survey data from all five Gulf states. Region-specific hyperparameters for catchability and observational error were estimated from global priors. We conducted alternative model runs to evaluate the sensitivity of parameter estimates to the inclusion of different IOA. Biomass trajectories for base and alternate models were compared for the stock from 1984 to 2016. We found the model was insensitive to removal of IOA and all models showed patterns of declining biomass over the time period examined. The utility of thi modeling approach is that it can be used for the determination of stock and fishery status of the Blue Crab stock at regional and Gulf-wide scales and be used to understand those states and regions that exhibit relatively greater uncertainty in relative abundance from process and observation error.

The University of Southern Mississippi
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