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
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/29129 |
| Date | 23 February 2005 |
| Creators | Gallagher, Charmaine Marie |
| Contributors | Langdon, Chistopher J. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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