• The Journal of Fisheries Business Administration
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• v.33 no.2
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• pp.75-98
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• 2002

As a contribution to developing fishery stock assessment, optimum sustainable yield and its international standards such as MSY, MEY, and dynamic MEY for six recommended fisheries are developed using bio-economic models. For selecting the appropriate model, five models - Schaefer, Schnute, Walters and Hilborn, Fox, and CY&P models are tested in effort and catch data of six species. Surprisingly all the models except the CY&P model failed to satisfy statistical standards such as goodness-of-fitness and reliability. Generally, the CY&P model holds good fitness and statistically significant level for all of six fisheries. However, the CY&P model for squid, where the intrinsic growth rate is high, could not explain MSY, MEY, and dynamic MEY appropriately. This study makes a contribution to develop the modified model for the intrinsic growth rate of 1. The reformulated model represents the results reasonably even though the estimated equation has not good fitness. Although most of the CY&P models appear to have good fits and validated results for some cases, these models also seem to be quite sensitive to parameters which means a more stable model should be developed and data should carefully be handled. In particular biological and technical interactions such as multispecies, predator prey relationship, age structure and mortality should be taken into account. In addition, economic factors and fishing efforts such as price, cost, technical change and a reasonable function of fishing input should simultaneously be considered.

• Environmental and Resource Economics Review
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• v.12 no.2
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• pp.299-325
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• 2003

This study uses Conrad's model(nominal fishing effort) of a fishery to analyze theoretically the effects of cost changes on fishing effort, harvest level, and stock size. Static and dynamic open access effects are also modeled present value maximizing scenarios through simulations, and compared an extended model, Cunningham's model(diminishing fishing effort). Results show that an increase in the unit cost of effort goes up the fish stock in static open access, but open access dynamics shows the exhaustion of fish stock as the unit cost of effort decreases. In conclusion, we can derive the optimal equilibrium of resource, given conditions and parameters, as well as utilize this comparative statics to efficient fishery management.