Adaptive Harvesting in a Multiple-Species Coral-Reef Food Web
Daniel B Kramer, Michigan State University
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The utility of traditional bio-economic harvest models suffers from their dependence on two commonly used approaches. First, optimization is often assumed for harvester behavior despite system complexity and the often neglected costs associated with information gathering and deliberation. Second, ecosystem interactions are infrequently modeled despite a growing awareness that these interactions are important. This paper develops a simulation model to examine the consequences of harvesting at two trophic levels in a coral-reef food web. The model assumes adaptive rather than optimizing behavior among fishermen. The consequences of changing economic, biological, and social parameters are examined using resilience as an evaluative framework. Three general conclusions are reached. First, the simulated ecosystem is sensitive to small changes in economic, biological, and social parameters. Second, threshold effects are common. Third, as compared to results typical of traditional single-species optimization models, some results are counter-intuitive. Benefits of this approach are that the model affirms and adds to the results of traditional bio-economic harvest models, is empirically operational, and provides a richer selection of policy alternatives. Finally, the analysis of trade-offs in terms of resilience provides a useful evaluative framework for multiple-species harvest models.
fisheries; resource economics; coral reefs; resilience; adaptive behavior; food web; simulation