The purpose of this study is to investigate optimal exploitation of a Pacific salmon fishery under the assumption that exclusive property rights in a fishery have been vested in a single or sole owner. Based on a review of the existing fisheries economics literature which focuses largely (but not entirely) on long-term steady state analytics, it is argued that the associated modeling technique does not apply readily to Pacific salmon fisheries. This line of reasoning is supported by the development, along the lines of the existing literature, of both a within-season and a long-term model of a salmon fishery. The within-season model, which finds limited precedent in the literature, provides the opportunity to introduce two relationships important in anadromous salmon fisheries, i.e., a production function with a catch coefficient variable at the vessel level and a stock distribution function, or time-of-entry curve. An analytical general solution is obtained to the model incorporating these features. The intertemporal model incorporates a purely compensatory Ricker-type spawner-recruit curve to define the interseasonal relationship between spawning escapement and future recruits. This model is formulated as an optimal control problem and is solved by using the general form solution to problems of this type which has recently been developed in the literature. A numerical solution to optimal escapement from the Skeena River fishery is obtained for parameters and coefficients estimated from this fishery. Both models have signficiant shortcomings which motivate the development of a more complete model of the fishery. Though it retains the basic features of the within-season and intertemporal models, this larger model allows concurrent within-season and interseason analysis, contains two species in a joint harvesting technology, contains an age structure and a stochastic element, all of which are absent in the two earlier models. This model is simulated on a computer in two formulations -- one dealing with weekly fleet hiring by the sole owner and the other with annual fleet hiring. The alternative fleet hiring assumptions are introduced so as to assess the added efficiency which is provided by more flexible fleet hiring rules which would be an important feature of coast-wide attempts at rationalizing the British Columbia salmon fishery via establishment of property rights. The major findings of the study are several. The determination of an optimal escapement policy via simulation experimentation demonstrates that a computer model of this type can successfully be used in this fashion. The specified minimum annual escapement which maximizes the present value of net profits was 300,000 sockeye and 400,000 pink for annual fleet hiring while the weekly fleet hiring model required the additional application of a weekly minimum escapement of 30% of the available total sockeye and pink stock. Comparing the results of the two fleet hiring assumptions it was concluded that the weekly fleet hiring regime resulted in a larger present value of net profits considering the Skeena River fishery alone. In .a comparison of the optimal fishing effort indicated by the simultion model (as measured in vessel-days) with the effort expended in the actual fishery it was concluded that a minimum estimate of excess effort is approximately .15% for annual fleet hiring and 50% for weekly fleet hiring. Successful development and application of this computer-based model is a significant step towards development of the larger coast-wide model which can be used to estimate optimal capacity for the entire fleet. / Arts, Faculty of / Vancouver School of Economics / Unknown

A computational procedure for optimization of large multidimensional models is presented. The procedure is applied to a model of the Georgia Strait sport and commercial fisheries of Chinook C Oncorhynchus tshawytscha ) and coho ( O. kisutch ) salmon. Optimal seasons for these fisheries are calculated and compared to current regulations. Differences, in form and performance, between the optimal seasons and present seasons are minimal and insignifigant. However, in order to match present age structure, population levels and harvests a value of near zero must be placed on fish left in the water at the end of the season. The computational requirements of the optimization are proportional to those of the model. In the case study in this thesis the optimization required approximately eight to ten times the computer time of the model. / Science, Faculty of / Zoology, Department of / Graduate

Thesis (Ph. D.)--Oregon State University, 2001. / Typescript (photocopy). Includes bibliographical references (leaves 334-368). Also available via the World Wide Web.

The ex-vessel coho salmon market has been paid scant attention in the study of the salmon resources. This study is an attempt to advance an understanding of the variations of ex-vessel prices and landings during the coho season as well as between the various coastal ports where the fish is landed. This study presents an empirical analysis of the ex-vessel port markets for coho salmon in Oregon and Washington. The objectives of the study are to investigate the variation in landings and prices during the fishing season and to compare those differences between ports for both states. This study focuses on the determination of the ex-vessel price mechanism and the decision behavior of coho fishermen in their choice of ports to land the catch. An economic model of each port is developed to explain the buying behavior of processors and the selling behavior of fishermen. Each port is treated as a distinctive market subject to external changes in the abundance of coho, the conditions of the wholesale markets, and the responsiveness of fishermen to prices in other ports. Several econometric models are constructed to determine the distinctive characteristics of the Oregon and Washington ex-vessel port markets. The demand and supply at the different ports are estimated by applying regression analysis to 32 different sets of data. These data include a single year (1976) of transaction records for the twelve Oregon ports, and four years (1973-1976) of landings records for the five Washington coastal ports. Three different models are used; a simultaneous equations model, a recursive model, and a single equation model. The major findings in the study are as follows: the ex-vessel demand in most Oregon or Washington ports is highly elastic, which suggests that changes in seasonal landings at a port do not have any significant impact on the ex-vessel price. While fishermen and other industry observers have noted differences in seasonal ex-vessel price between ports, such differences do not appear to exist. Average seasonal price differences between ports do not vary when appropriate weights are applied to the average price calculations. The size (in pounds) of the coho salmon plays a major role in the determination of the intraseasonal ex-vessel demand at all ports. Estimations performed without accounting for this variation fail to adequately explain ex-vessel price variation. Another variable found to be a key factor in the explanation of ex-vessel prices is the wholesale price. This factor and the size variable accounted for most of the variation in ex-vessel port prices. Even though the seasonal prices between ports are similar, the intraseasonal variation in port price is partly the result of competition for the fisherman's catch of coho. When two ports are located in such a way that fishermen may easily land at either one, fishermen appear to land at the port where price is greater. Ports such as La Push and Neah Bay in Washington, and Bandon and Winchester Bay in Oregon are the ports found to be alternative ports for the fishermen catching coho in those areas. Coastal ex-vessel prices do not appear to be established as a result of equilibrium conditions at any particular port. Rather, ex-vessel price and market clearing quantities are determined in the aggregate. Each port's buyers will establish port price based on the current aggregate equilibrium condition. The aggregate coastal demand for coho at the ex-vessel level was estimated for the 1976 season and found to be highly price elastic. Given that aggregate supplies are augmentable, increases in coastal landings will increase total returns to the ex-vessel fishery. One additional finding suggests that the number of buyers in most ports does not play a significant role in the determination of intraseasonal variation of port ex-vessel prices. / Graduation date: 1979

Recent legislative changes have increased the need to monitor contamination effects in Scottish waters and have consequently elevated demand for research into vertebrate and invertebrate ecotoxicological techniques. Selected invertebrate ecotoxicological techniques were used to measure the effects of two industrial contaminants found in Scottish sea lochs i) the synthetic pyrethroid cypermethrin, licensed for treatment of lice infestations in the Scottish salmon farming industry and ii) polycyclic aromatic hydrocarbons (PAHs) released into Loch Leven via the Kinlochleven aluminium smelter. Mytilus edulis accumulated cypermethrin during exposure and exhibited shell closure behaviour. Neither neutral red retention (NRR) time of lysosomes nor aerial survival were affected by concentrations £1000 mg/l. As the shell closure effect occurred at concentrations greater than typical field concentrations (i.e. within and around almost sea cages), Mytilus does not demonstrate suitability for use as a study species when monitoring the biological effects of cypermethrin exposure. Carcimus maenas exhibited 50% mortality after 96 hours of exposure to the salmon treatment dose of 5 mg cypermethrin/1. Exposed crabs exhibited a tetanus-like behaviour. Sensitivity to cypermethrin was comparatively greater inCarcinus than in Mytilus . Activity of the detoxification enzyme glutathione S-transferase (GST) was assessed as a potential biomaker of exposure. GST activity was induced in crabs after 7 days of daily exposure to cypermethrin concentrations of 50 mg/l and 500 ng/l. Although GST activity was sensitive to cypertherin exposure, the brevity of the GST response reduces scope for its use as a biomarker for cypermethrin exposure in the field. Some of the techniques investigated here offer potential for further development and possible implementation into monitoring strategies for the Scottish coastal environment.

There is great interest in the perceived conflict between salmon fisheries and seals, but little information to inform managers.  This study therefore explored the interactions between harbour seals and salmonids within an estuarine system, the Cromarty Firth, NE Scotland (57°37’N, 4°21’W).  The number of seals using this area in the 2000 pupping season was estimated to be 188 (138-286) using a novel Bayesian framework that corrected counts of seals on land for those remaining in the water. The presence of seals in the mouth of the River Conon, at the head of the Firth, and the occurrence of salmonid otoliths in seal scats, were related to changes in the abundance of adult salmonids.  Overall, salmonid otoliths were found in 8% of scat samples and 21% of those collected during July.  This represents the highest reported incidence of salmonid otoliths from scat samples collected in the UK;  it is not clear if this is due to temporal or geographic differences with previous work. A novel diet estimation technique was constructed based on the assumption that seals may be employing one of a range of possible foraging strategies.  This estimator was compared to two established methods and it was found that model choice introduced considerable introduced considerable bias (up to 3x) in the estimated importance of salmonids in the diet.  It is unclear which of the models is appropriate and their outputs were combined to represent uncertainty in our estimates of diet more fully. It was not possible to partition consumption of salmonids between salmon and sea trout as otoliths were too badly digested to allow identification of species.  A simple food web was used to suggest that removal of seal predation may improve fishery catch by 17% (5-52%).  This figure must be treated with caution and potential biases, and caveats, are discussed.

This thesis focuses on transactional process involved in the construction and operation of the Kuskokwim River Salmon Management Working Group. This cooperative wildlife management mechanism gives Yup'ik commercial and subsistence fishermen and other users a direct role, with the Alaska Department of Fish and Game, in salmon management. / Transactions involving participants' knowledge and values are described in three processes: (1) the establishment of a management body and its operating rules; (2) the mediation of power in decision-making; and, (3) fishery management which uses both "science" and "fishermen's knowledge." / Results indicate that through cooperation in decision-making, data gathering, and other management tasks the participants have been able to promote record commercial salmon harvests while at the same time providing for subsistence and conservation needs. Shared local values of consensus and reciprocity have acted to sustain participants' interaction in the bargaining process inherent in co-management. Through having to mediate and accommodate diverse interests and goals, the participants have developed a significant congruency or compatibility of values.

Graduation date: 1975

Rates of mortality among young salmon passing through a high speed, model propeller, turbine operating under a 50 ft hydraulic head but under various, draft tube suctions are given. Effects, on both fish mortality and turbine performance, of admission of compressed air into the turbine at various locations to reduce the effect of cavitation (believed to be the major cause of fish mortality in the turbine) are discussed . At low turbine speed and low efficiency, admission of air immediately downstream from the blades reduced the mortality of fish substantially but at high turbine, speed, and high efficiency, the reduction was insignificant. At high turbine speed, the effect, on fish mortality, of admitting compressed air into the penstock and atmospheric air into the turbine draft tube through a 3" diameter steel pipe installed about 1 ft downstream of the blades are shown to be beneficial. Records of biological examination from some of the tests to determine the apparent type of injuries are included. An attempt has been made to correlate the turbine speed with the number of injuries likely to be caused by fish being hit by the blades.The effect of partial vacuum on fish is also given. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

The exploitation of salmon resources was once central to the economic life of the Northwest Coast. The organization of technological skills and information brought to the problems of salmon utilization by Northwest Coast fishermen was directed to obtaining sufficient calories to meet the requirements of staple storage foods and fresh consumption. This study reconstructs selective elements of the traditional salmon fishery drawing on data from the ethnographic record, journals, and published observations of the period prior to intensive white settlement. To serve the objective of an ecological perspective, technical references to the habitat and distribution of Pacific salmon (Oncorhynchus sp.) are included. The aim of the work is to assess the relationship of salmon technology complexes to ecological conditions at fishery sites. It is an examination of the operating principles in traditional systems of salmon production. A model of the fishery is suggested: during migration anadromous salmon pass through a number of time and space segments where they can be intercepted by fishermen. A coincidence of appropriate elements will define a fishery site, i.e., the characteristics of the prey, accessibility to resource locations, natural features of the environment, and the enterprise of fishermen. The interaction of these and their constituent variables provides a range of selective strategies to be used, analyzed in this study with reference to specific Northwest Coast ethnic divisions and geographic locations. Twenty-four ethnic or areal divisions within the Northwest Coast culture area were studied. The results of the research are presented in Part One supported by distribution maps and illustrative materials. Lists of reference tables for each of twelve systems of salmon production are contained in an Appendix. Part Two includes technical information about Oncorhynchus sp. and its habitat. Part Three is an analysis of social, ecological, and technological elements in several stages of inter-relation, including an interregional comparison in the final section. An Index of Salmon Abundance and a comparison of selected resource areas provide statistical evidence (Appendix II and III). / Arts, Faculty of / Anthropology, Department of / Graduate