Prioritization in ecosystem-based fisheries management: Optimizing for multiple species and multiple objectives

Background/Question/Methods High economic value of a top predator and lower profit from targeted and bycatch prey species would intuitively suggest that (1) the top predator should be fished heavily to maximize profit, and (2) prey should be fished at low levels (or not at all) in order to maximize their contribution as sustenance to the upper trophic level.  However, lower trophic levels are likely to have a higher turnover rate which could sustain both fishing and predation pressure, therefore optimal harvesting of the prey may actually be higher than predicted.  By utilizing a multispecies bioeconomic approach for a Caribbean reef community, we determine the optimal harvesting rates for both predator and prey species and then ask how this more comprehensive optimization differs from single-species management approaches.  We then expand our trophic analysis to ask how our predictions would change with three different ecosystem-based management objectives that explicitly value abundance of the bycatch prey (Stoplight parrotfish) which are important grazers in the community, abundance of the predator (Nassau grouper) which may be desired for its intrinsic value and snorkeling tourism, and overall biodiversity. 
Results/Conclusions Our preliminary findings show that the intertwined tradeoffs inherent to fisheries management can result in temporary or permanent fishing moratoriums on the prey as its intrinsic value increases, compared to continuous fishing at low levels when we optimize the model solely for profit from fishing.  Using this tractable dynamic optimization approach for a variety of objectives will also allow us to examine the sensitivity of management objectives to trophic interactions that cannot be uncovered in static assessments such as those that rely solely upon the distribution of critical habitat.