Operational Model to Evaluate Assessment and Management Procedures for the North Pacific Swordfish Fishery

摘要

By contrast to several tuna species, relatively little is known about swordfish, and the associated catch and effort statistics are characterized by a substantial level of uncertainty and incompleteness. An operational model was designed to help evaluate the performance of stock assessment and fishery management procedures in this 'data poor' context. This model incorporates key features of age-structured and length-based models and accounts for growth, reproduction, mortality, recruitment, exploitation, and movement. It can be used to project trends in abundance, catch, and stock composition, recruitment patterns, spawning biomass, and so forth, for multiple stocks and fleets, under user-specified levels of process and observation error, sampling regimes, and exploitation patterns. This model has been used to test the performance of stock-assessment procedures and generate preliminary estimates of biological reference points for specific combinations of hypotheses about the fishery. This manuscript describes the features of the model, its underlying hypotheses, limitations, and user interface. The results of probing studies conducted so far are also presented.