SEDAR 85 Gulf of Mexico Yellowedge Grouper Operational Assessment - Additional Projections

In preparation for the Gulf of Mexico Fishery Management Council’s Scientific and Statistical Committee (SSC) review of SEDAR 85, additional projections were developed based on alternative recruitment scenarios in the late assessment period (2013-2021; where recruitment deviations were not estimated) and projection period (2022+), along with alternative Maximum Sustainable Yield (MSY) proxy values. Given the life history of Yellowedge Grouper (maximum age of 85 years) and their vulnerability to overexploitation, a higher spawner potential ratio (SPR) may be more appropriate for this hermaphroditic species. Simulations conducted by Harford et al. (2019) suggest that SPR ratios of 40% or 50% led to the highest probabilities of achieving long-term MSY for hermaphroditic stocks. They found that more conservative fishing mortality proxies were required to achieve MSY-based fishery objectives when steepness was “least certain” (i.e., uniform prior). Steepness for Gulf of Mexico Yellowedge Grouper was fixed at a biologically plausible value because it was not estimable within the SEDAR 85 OA Base Model and was highly uncertain.