Using an Expert System to Evaluate Vulnerabilities and Conservation Risk of Marine Fishes from Fishing

Today, fishing is the only large-scale wildlife hunting activity. Unsurprisingly, it has contributed to the depletion and extirpation of numerous marine fish populations. We develop a fuzzy logic expert system to estimate the risk of depletion of marine fish populations from fishing. The frrst component of this expert system predicts the intrinsic vulnerability of marine fishes (i.e., fishes' inherent ability to withstand fishing mortality) from simple parameters of life history and ecology. The second component infers exploitation status of fishes from temporal features of their catch time-series. Combining the predicted intrinsic vulnerability with the inferred exploitation status, the expert system predicts the relative depletion risk of marine fishes. Heuristic rules relating the various input attributes with depletion risk are derived from published literature and expert opinions. Using published datasets and simulated data from numerical population dynamic models, we show that the expert system provides robust proxies of intrinsic vulnerability and relative depletion risk from fishing. Based on the validated system, we estimate relative depletion risk for 460 exploited marine fish species for which long catch time-series exist. Extrapolating our findings to all marine fishes, we estimate that a large proportion of marine fishes are facing high depletion risk from fishing. Our work suggests that marine fish may have a similar conservation risk from large-scale human activities to those of other vertebrates, and thus are candidates for a similar level of orresponding author: Fisheries Centre Aquatic Ecosystems Research Laboratory (AERL), 2202 Main Mall, The University of Briti h Columbia, Vancouver, B, anada V6f 1Z4; Tel: +1 (604) 822-2731; fax: +1 (604) 822-8934; Email: w.cheunglsheries.ubc.ca 26 William W. L. Cheung, Tony J. Pitcher and Daniel Pauly conservation attention. The tudy highlights the potential applications of an expert system in the study of the conservation biology of fishes.