Movement Ecology and Trophic Dynamics in the northern Gulf of Mexico: Implications for Fisheries Management

The northern Gulf of Mexico (nGOM) is a diverse and productive region for living marine resources. The region supports lucrative commercial and recreational fisheries ranging from low-trophic-level species, such as penaeid shrimps and forage fishes, to high-trophic-level predators (e.g. Yellowfin Tuna). This thesis contributes to the region’s ecological knowledge, with the primary aim of enhancing management efforts and providing direct management advice to two important fisheries. In Chapter 1, we develop a traditional per-recruit model for Southern Flounder, as well as a spatiotemporally integrated per-recruit model that incorporates the spatial distribution of fishing effort and the stock’s movement ecology. Fish movement was informed using n = 80 acoustically tagged individuals. Chapter 1 expands upon our understanding of the movement ecology of Southern Flounder and using a novel modeling approach, we evaluate management strategies for the stock. Chapter 2 employs a multispecies trophic model that integrates stomach contents and biotracer data into a single modeling framework to assess the trophic interactions of 41 finfish species and their prey. Many of these species, such as Spotted Sea Trout, Red Drum, Southern Flounder, and Gulf Menhaden, are of significant economic importance to the region. This chapter refines our understanding of the region's trophic dynamics and offers the ability to inform future ecosystem models. Overall, this thesis contributes to knowledge concerning the Southern Flounder’s spawning season movement dynamics and provides a framework for managing this iconic, yet declining, species, as well as enhances our understanding for many of the nGOM’s complex trophic relationships.