Abstract

Coral reef ecosystems, such as the well-studied La Parguera reef system (SW Puerto Rico), exhibit complex interactions with consequences difficult to predict with conventional fisheries management models. A newly-developed trophic model, based on Ecopath with Ecosim, offers an alternative means to evaluate fishing policies that might achieve desirable ecological and social outcomes, to compare the system to other modeled reef ecosystems, and to explore data and data gaps. The model is based on fisheries and ecological data, primarily centered on species of commercial and ecological importance, grouped by habitat prefer-ences. It has been balanced for current conditions although additional fisheries data (recreational and ornamental) need to be included to improve the representation. The model construction process identified gaps in available data (e.g., diet compositions, metrics of fishing effort, landings, and estimates of primary production) and balancing raised interesting ecological questions. Some groups, such as parrotfish appear to be so underutilized as prey that the accuracy of biomass estimates and our understanding of predator-prey relationships are questioned. Although model structures vary, complicating direct comparisons, a similar Caribbean model built for the 1970 - 1980s estimated total biomass 5.6 times higher than the present model. Changes of this magnitude, if accurate, highlight the need for further study of the roles fishing and environmental changes have played in reshaping this system over the last 30 - 40 years. This modeling effort identified data needs, generated hypotheses for future research, and provides an initial look at ecosystem-based fishery management scenarios for this reef system.

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