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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Integrating fleets, markets and ocean dynamics : a bioeconomic analysis of the Oregon ocean shrimp fishery

Gallagher, Charmaine Marie 23 February 2005 (has links)
Questions relating to economic performance, biological conservation and variation in resource abundance and harvest of ocean shrimp have led to increasing pressure for management action. Developing effective management policies for this highly variable resource requires a comprehensive understanding of the fishery and marine processes. Important factors in understanding the fishery include oceanographic influences on shrimp distribution, abundance, and fishery and market dynamics. Fishery regulations for Oregon ocean shrimp, Pandalus jordani, are designed to protect age one shrimp from overharvest and sustain long-term fishery benefits. The research presented in this dissertation describes the development and analysis of analytical models ranging from classical, biological based yield-per-recruit management approaches to optimization models that incorporate economic variables and environmental recruitment relationships. This research is composed of three separate but complimentary papers regarding management of the ocean shrimp fishery. In the first paper, a yield-per-recruit analysis found that high natural mortality rates lead to yield maximization by selecting relatively young shrimp. The revenue-per-recruit analysis found that by delaying the season opening date, shrimp revenue would generate higher total revenues, while decreasing total fishing mortality and harvest. The second paper utilized a nonlinear optimization model with cost and market information to compare harvest strategies on fishery yield, gross revenue and discounted net present value (NPV). A key extension modeled a vertically integrated fishery from harvest through processing and compared harvest strategies based on wholesale prices, shrimp quality and processing yields. The optimization model that generated high yields exhibited high levels of effort and landings but low profits and NPV. The revenue policy maximization resulted in allocation of seasonal effort that produced high value older shrimp. NPV maximization generated high value shrimp landings with lower seasonal effort. Variability in shrimp recruitment and the impact on fishery utilization, income and efficiency was analyzed in the third paper. The optimization model that incorporated a stock recruit relationship and effects of environmental variables indicated an optimal harvest strategy that protects the spawning stock within a season and closes the fishery in years of poor recruitment. The results of this research highlight the complexity of management decisions when environmental forces and economic factors are jointly considered. / Graduation date: 2005

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