Simulated response to harvesting strategies in an exploited ecosystem in the southwestern Gulf of Mexico

The impact of some optimized harvesting strategies on ecosystem structure was investigated using a mass-balanced model of the ecosystem in the southwestern Gulf of Mexico, where there are four types of artisanal fisheries and a shrimp fishery that has collapsed. The Ecopath with Ecosim software was used to simulate harvesting strategies aimed at optimizing economic (profit), social (jobs), ecological (conservation of ecosystem structure) and shrimp-recovery criteria. As expected, the ecosystem changes that would ensue vary according to the combination of optimization goals. We found that for some scenarios, the extraction of biomass from a discrete trophic level changes, impacting ecosystem and catch structure. This was clearly observed through the tendency of the mean trophic level of the ecosystem and catch, as well as the fishing-in-balance index (FBI). A particular discussion was made about the collapsed shrimp fishery, where the impact of a specific shrimp-recovery strategy was evaluated. Collapse is strongly associated to physical variables and recovery based on trophic relationships is plausible but with a high ecosystem structure cost.