COMPARISON OF MARINE PROTECTED AREA POLICIES USING A MULTISPECIES, MULTIGEAR EQUILIBRIUM OPTIMIZATION MODEL (EDOM)

A multispecies, age-structured spatial model called EDOM is developed and used to evaluate impacts of multiple fishing fleets and marine protected areas on long term (equilibrium) fishery economic performance, catch, and abundance. Populations and fishing are represented on a grid of spatial cells, with linkage among cells due to larval and adult dispersal and inclusion of multiple cells in the home ranges of fish that are resident in or home to each cell for spawning. Recruitment to each cell is assumed to depend on area of suitable juvenile rearing habitat and on compensatory survival responses after larval settlement. Spatial fishing efforts are predicted using either gravity models or an economic optimization that distributes effort so as to maximize total profit for each fleet. The model predicts that imposition of MPA networks designed from habitat criteria will result in improved economic performance only if fishing effort is sub-optimally high outside reserves. Absent such MPAs, it can still be optimum to close some source or nursery areas to fishing, if larval dispersal results in a source-sink metapopulation structure and/or fishing in important nursery areas causes high bycatch mortality of pre-recruit juveniles