Developing an Ecosystem-Based Approach to Management of the Gulf Menhaden Fishery Using Ecopath with Ecosim

The Gulf of Mexico (GoM) is a valuable ecosystem both socially and economically, and fisheries contribute substantially to this value. Gulf menhaden, Brevoortia patronus, support the largest fishery in the Gulf (by weight) as well as provide forage for marine mammals, seabirds and commercially and recreationally important fish species. Understanding the complex interactions among multiple fisheries and myriad unfished species requires different tools from those used in traditional single-species management. Ecopath with Ecosim (EwE) is increasingly being used to construct food web models of aquatic ecosystems and to evaluate fisheries management options. An EwE model is developed to examine the impact of the menhaden fishery on both fished and unfished species in the GoM. This model builds on previously published EwE models of the GoM, but is tailored to the range and habitat of Gulf menhaden. A number of different harvest strategies for the menhaden fishery are modeled and the results are evaluated in terms of impacts on other fisheries and unfished predator populations. The results of the model simulations allow for estimation of a level of Gulf menhaden catch that satisfactorily accounts for predator-prey interactions and aid in the development of ecosystem-based policy for the Gulf menhaden fishery.