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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

Strategy selection in the Oregon trawl fisheries

Harman, Ellen Jean 01 October 1987 (has links)
The ocean fishery is an example of a common property resource industry. Behavior of commercial fishermen is determined by a complex set of economic, environmental and social factors. All of these factors contribute to the individual fisherman's success. Fishermen learn to cope with the variability inherent to their occupation. Two strategies are observed in fishing behavior: The specialist who operates exclusively in one fishery and the generalist who readily switches fisheries according to market, social or management considerations. Traditional fishery models formulated to predict the behavior of fishermen have focused on the specialist. Smith and McKelvey (1986) and McKelvey (1983, 1987) have provided analyses to suggest these two fishing strategies may co-exist in a fluctuating environment. The purpose of this study is to analyze the Oregon trawl fisheries for the presence of diversification in strategy selection. To gather the data necessary for testing the hypotheses, interviews were conducted in the trawl fisheries of Oregon, June through December 1985. Three groups of fishermen are identified according to strategy selection. Nominal effort differences and capital-to-income ratios are examined for each strategy type. Additional analysis is done to look at the components of income determination through regression analysis. Discriminant analysis is used to examine the fishermen's attitudes toward switching, risk and management concerns. Among the findings of this research is that specialists and generalists do exist but they cannot adequately characterized by exclusively economic measures. Attitudes shown on the part of the fishermen indicate they feel that management is a significant factor contributing to income variability and strategy selection. / Graduation date: 1988
2

Fishing location choices in Oregon trawl fisheries : are fishermen risk-averse or risk-prone?

Trisak, Jiraporn 22 November 1994 (has links)
Despite the fact that fishing is an inherently uncertain business, risk has rarely been formally recognized in fisheries science or management. Few fishery management plans include any form of risk assessment and those that do focus on minimizing risk caused by uncertainty associated with markets and environmental conditions. Fishermen's attitudes towards risk, whether they are risk-neutral, risk-averse, or risk-prone, have rarely been considered. Although fishermen's attitudes towards risk have been shown in theory to have an impact on fish populations, none of the previous investigations precisely identified whether fishermen are risk-neutral, risk-averse, or risk-prone. This research attempted to identify fishermen's attitudes towards risk from an analysis of their decisions about where to fish. The research applied risk-sensitive foraging theory to an analysis of data from the Oregon trawl fishery for 1991. The data were provided by the Oregon Department of Fisheries and Wildlife. One file contained tow-by-tow information for each fishing trip on landings by species, time spent fishing, type of gear, and fishing locations. A corresponding file contained trip-by-trip information on landings and price by species. The two data files were screened for inconsistencies and then classified into small homogeneous categories based on port, fishing gear, fishing area, and boat size. Various variance-discounting models were fitted to each category to determine fishermen's attitudes toward risk. The models describe the expected utility of fishing at a given distance from port as a linear function of the mean, variance, and third moment of the dollar value per hour of the retained catch. The unknown parameters were estimated from the data using logistic regression techniques. The results of the analysis indicated that in two of fifteen categories the fishermen were risk-averse, and in four categories they were risk-neutral. However, for the remaining nine categories the results were inconclusive and in some cases the fishermen's choice of fishing locations appeared illogical. Instead of preferring fishing grounds that generated higher profits, it appeared that fishermen actively avoided such grounds. The inconclusive and sometimes illogical results may have been due to inappropriate assumptions about the data and about the factors motivating fishermen's decisions. Additionally, there might have been some factors that could have affected the analysis which this research overlooked. For example, this research only accounted for monetary rewards, but fishermen may have preferences other than revenues and costs that influence their choice of fishing grounds. / Graduation date: 1995
3

Dynamic programming models of fishermen's choice of target species assemblage in the U.S. west coast groundfish trawl fishery /

Babcock, Elizabeth A. January 1998 (has links)
Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [120]-129).
4

A study of the trawler fleet investment decision within the demersal fishing sector

Flanagan, B. L. 12 1900 (has links)
Thesis (MBA)--Stellenbosch University, 1984. / BACKGROUND AND OBJECTIVE: The chief sector of the South African fishing industry, demersal trawling is in a state of uncertainty that brings its competitiveness and long term developnent into question. The Hake (Merluccius capensis and Merluccius paradoxus) resource, which accounts for 70% of the landed catch, has finally started on the expected road to recovery and it is anticipated that this will proceed shortly for a nunber of years. During 1983 comfort was derived from the resulting rise in catch per unit effort rates and a significant improvement in the average size of fish landed. This, together with lower fuel prices and increased operating efficiences, enable the industry to operate at lower expenditure. Unfortunately, a second successive reflection of the T.A.C. (Total Allowable Catch ) of 12% in 1983 meant that gains in productivity were not fully reflected in reduced landed costs. This year (1984) the T. A. C. was increased by 4,8% which only marginally improves the already poor situation. More serious difficulties can be traced to adverse market developments. The price of fish has fallen in real terms (see Table 1.1 below) over a number of years. However, in 1983, the industry experienced a startling fall in prices, the severity of which may be gauged from the fact that actual prices realised were roughly equal to those of 1981. (Bross, 8 May, 1984) This pattern is continuing through 1984 - as is seen in Table 1 .1, an extract from Irvin & Johnson financial results .
5

Essor et déclin de la pêche industrielle à La Rochelle (1871-1994) / Expansion and decline of industrial fishing in La Rochelle (1871-1994)

Moulinier, Henri 27 June 2014 (has links)
Située au coeur du golfe de Gascogne, La Rochelle fut dès sa naissance au début du XIIe siècle une communauté de pêcheurs. La ville s’affirme comme une cité marchande, devenant l’une des plus dynamiques de l’Ouest français. Son port de commerce se déplace sur un nouveau site en 1890, libérant le vieux port au centre-ville pour la pêche. De nombreux voiliers viennent déjà y vendre leur pêche sur un marché aux poissons attractif, que le chemin de fer relie à l’intérieur du pays en 1857. Une nouvelle page s’ouvre, celle du chalutage industriel qui fait une percée majeure en Grande-Bretagne. A La Rochelle, après l’échec d’une tentative de l’anglais Craggs d’y implanter le chalutage à vapeur en 1871, de grands armements à la pêche industrielle sont fondés de 1904 à 1920. Une première période d’essor de ces armements fait de la cité le deuxième port de pêche de France, le premier de l’Atlantique. Après le marasme des pêches françaises et la crise de la flottille de chalutiers à vapeur rochelais, un nouvel essor du port s’affirme après la Seconde guerre mondiale. La Rochelle redevient le quatrième port de pêche de France dans les années 1960. Mais l’année 1965 marque une rupture de la pêche industrielle rochelaise et un déclin s’ensuit qui conduit à la disparition des derniers grands chalutiers en 1994. De nombreux travaux menés jusqu’ici ont porté sur d’autres ports de pêche de France. Cette étude a l’ambition de contribuer à la connaissance de plus d’un siècle d’histoire de pêche industrielle du port de La Rochelle, de ses dimensions économiques, sociologiques, politiques et écologiques, dans le cadre d’une étude comparative, en analysant les caractéristiques et les raisons de cet essor et celles d’un déclin précoce et rapide. / Situated in the heart of the bay of Biscay, La Rochelle, right from its foundation, at the beginning of the XIIth century, was a community of fishermen. It then became one of the most dynamic cities in western France. In 1890 the commercial port moved to a new site, liberating the old port in the city centre for fishing activities. Many sailing ships came to sell their fish on an attractive fish market boosted by the railway connection to the inland part of the country in 1857. A new era started with industrial trawling, a major innovation in Great Britain. In 1871, the English shipowner Craggs tried to introduce steam-powered trawling but suffered a setback . However from 1904 to 1920 important armaments in industrial trawling were created, making La Rochelle, in this early period of expansion, the second fishing port in France and the first one on the Atlantic coast. After the stagnation of French fisheries and a crisis of Rochelais steam-powered trawlers, a new expansion of the port occured after WWII. In the sixties, La Rochelle became the 4th fishing port in France, until in 1965 a break in industrial fishing activities resulted in the loss of the last big trawlers in 1994. There have been numerous documents about other fishing ports in France. This study aims to concentrate on the history of industrial fishing in the port of La Rochelle over a century, highlighting its economic, sociological, political and ecological dimensions. For this purpose a comparative study has been made, analysing the characteristics and the reasons of this expansion as well as the ones of a rapid and premature decline.

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