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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

When Celilo was Celilo : an analysis of salmon use during the past 11,000 years in the Columbia Plateau /

Thomison, Patrick. January 1987 (has links)
Thesis (M.A.)--Oregon State University, 1987. / Typescript (photocopy). Includes bibliographical references (leaves 178-193). Also available online.
2

The share system and its effects on innovation, employment and income in the British Columbia salmon fishing industry, 1951-1961

Midgley, Ian Harold January 1963 (has links)
This thesis has been designed to examine the share system and to study its effects on innovation, employment and income in the British Columbia salmon fishing industry. The approach taken has been that of examining the theoretical basis of the share system and then noting how the system has worked in practice. The share system has demonstrated some notable advantages over a wage system in its approach in providing an incentive for hard work and in the economizing of materials used, Against these advantages must be weighed the heavy burden of risk which is shifted from the capitalist to labour. Share fishermen are not assured that they will earn any income from a particular fishing trip and may, in fact, be forced to bear part of the losses of those ventures which fail. The share system creates a rigidity in the free movement of resources within the fishing industry by requiring that the net proceeds from fishing be divided between the crew and the vessel owner in fixed proportions. The allocation to labour of a fixed percentage of all net income results in the entrepreneur requiring a higher rate of return on his investment than would be the case if he were operating in a freely competitive market, thus in theory the share system would inhibit innovation,, The entrepreneur requires that his investment projects have a sufficient return to repay both his capital and interest after paying a share to labour. The number of licensed fishermen and fishing boats has increased annually since 1951. The opportunity of obtaining a high income which is a feature of the share system is a particular incentive which attracts new recruits into the industry. However, many fishermen fail to remain in the industry due to the low and unstable earnings they experience. The incomes of British Columbia salmon seine fishermen appear, on the average, to be below those offered in alternative occupations, though there are certainly some very high incomes earned by a few fishermen0 The increased employment both of labour and capital can, in the main part, be blamed on the common property feature of sea fisheries. The share system, though playing a part in the total industry, is not the most important variable, A solution to the difficulties that the industry faces can best be sought by changes and adjustments elsewhere. / Arts, Faculty of / Vancouver School of Economics / Graduate
3

Selective action of gillnets on sockeye (Oncorhynchus nerka) and pink salmon (O. gorbuscha) stocks of the Skeena River system, British Columbia

Todd, Ian St. Pierre January 1969 (has links)
Exploitation of Skeena River sockeye salmon (Oncorhynchus nerka) has been conducted almost solely by drift gillnets since inception of the commercial fishery in 1877. Selective action of gillnets is a factor which may have contributed to a long term decline in sockeye production and to other features of the population biology. This study was designed to determine the selective properties of nylon gillnets presently in use; to compare these with properties of linen nets used prior to 1955; to adjust age composition estimates of escapement levels prior to 1946; and to re-examine brood year production. In addition, the selective action was examined of the fishery as a whole on sockeye and pink salmon (O. gorbuscha) in 1968. The selective properties of six nylon gillnets ranging in mesh size between 4-5/8 inches and 5-5/8 inches, which corresponded with sizes normally used in the commercial fishery, were to be determined through a simultaneous fishing experiment, and selectivity curves were computed by Holt's (1963) normal probability technique. Unique selectivity curves for each mesh size could not be determined from the sockeye data. Mean size of age class l.2 sockeye (representing about 12 per cent of the sample) increased with mesh size but mean size of age class 1.3 sockeye (representing about 82 per cent of the sample) demonstrated no trend. Age class 1.3 sockeye were among the largest on record and it was postulated that fish of this age class were too large to gill properly in all mesh sizes used. A comparison of the predominant mesh of nylon gillnet (5-1/4 inch) with linen nets of the mesh used in the historic fishery (5-5/8 inch) was also influenced by the large size of age class 1.3 sockeye. Nylon nets were 2.5 and 2.7 times as efficient as linen for sockeye, and 8.0 and 9.0 times as effective for pink salmon. Nylon gillnets, although smaller, caught larger sockeye and pink salmon than did the linen gillnets. Variances about mean size of sockeye and pink salmon were also greater for catches in nylon as opposed to linen gillnets. In total, the selective properties of the commercial fishery reflected the results obtained in the nylon gillnet multi-mesh experiment. An overall selectivity curve computed for sockeye salmon by the direct method of Regier and Robson (1966) approximated a skew-normal distribution. Examination of the age-sex class components of the stock indicated that selection increased linearly over the length range of age 1.2 sockeye of both sexes, and decreased linearly over the length range of age class 1.3 sockeye. A selectivity curve was also computed for pink salmon and this curve, in total, also assumed a normal shape in spite of the extremely small size of pink salmon in 1968. The length-girth relationships of the two species were shown to differ and this accounted for most of the difference between the selectivity curves. The relationship between maximum efficiency and the maximum girth to perimeter mesh measure closely approximated the value of 1.2: 1.0 reported by McCombie and Berst (1969) for other species. Retention by gillnets declined once the girth/mesh ratio exceeded 1.2 for sockeye. For pink salmon, no females were of a size to equal this ratio; the descending limb of the selectivity curve was due solely to males as the retention rates declined once girth/mesh ratio exceeded 1.0. These findings suggest that in most years the gillnet fishery on the Skeena River would tend to select relatively larger sockeye salmon. In years such as 1968, however, selection would be against smaller fish. This frequent reversal combined with the intense modern fishery, which tends to remove virtually all fish during a short period and allows almost complete escapement in periods between fishing, suggested that selective fishing has probably not been a significant factor in decreased production. / Science, Faculty of / Zoology, Department of / Graduate
4

An analysis of factors affecting resource usage in the Pacific Coast salmon fishery

Aungurarat, Peerarat 06 August 1970 (has links)
Graduation date: 1971
5

The mystery fish of Bonavista North : a multidisciplinary approach to research and management of a unique recreational salmonid fishery in Newfoundland /

Sutton, Stephen G., January 1997 (has links)
Thesis (M. Sc.)--Memorial University of Newfoundland, 1997. / Bibliography: leaves 102-111.
6

Expectancy-value theory as a tool in resource analysis and management : a study of the motivations of salmon anglers on the Salmonier River /

Bull, Peter Allan, January 1997 (has links)
Thesis (M.A.), Memorial University of Newfoundland, 1998. / Bibliography: leaves [219] -240.
7

Estimation of average and incremental net economic values of Oregon ocean sport-caught salmon : an aggregated travel cost approach

Raja Abdullah, Nik Mustapha bin 30 November 1988 (has links)
The main objective of this study was to estimate the demand for and value of Oregon ocean sport-caught salmon fishery. The primary technique employed to estimate the recreational demand was an aggregated zone average travel cost method (TCM). The willingness of an angler to pay was deduced from the estimated demand for recreational fishing. The concept of consumers' surplus was used in conjunction with the travel-cost based demand functions to estimate the net economic value of Oregon ocean sport-caught salmon. The net economic value computed for the pooled data from all ten ports was found to be about $6.4 million. This value was calculated based on the total travel cost per mile of one-way distance equal to 72 cents. The regional travel cost method (RTCM) was developed to measure the effects of substitutes and quality variables in the travel cost model. A system of a linear demand equations for the six larger ports was estimated by the seemingly unrelated regression equation (SURE) method. The substitute distances as proxies for substitute prices were found to be insignificant for this model. Likewise, attempts to include substitute distances using indexes constructed by the Principal Component analysis failed to give significant results, with the exception of Garibaldi and Brookings. The total net economic value for the regional travel cost model estimated by SURE was $9.1 million. The incremental value per coho equivalent was also assessed by using the relationship between catch and effort per month by port. The coho equivalent was constructed on the basis of average weights of the commercial salmon catch, which was roughly two coho to one chinook salmon. The weighted average incremental value per coho and chinook was found to be $23.46 and $43.17, respectively. These values were about 50 percent of their respective average values. A total of 66 out of 234 distance zones created had zero values. Tobit analysis was employed to efficiently estimate the recreational demand from this kind of data. From the estimated demand function, a net economic value of about $12.7 million was obtained. This value was higher than those estimated by the SURE method and the OLS in the simple model. It should be noted that all the above value estimates were based upon demand models that were not consistent with the theory of consumer demand. However, a theoretically consistent system of demand equations was estimated and presented in Appendix D. This model fitted the data better than the other models and should give more accurate estimates of consumer surplus. / Graduation date: 1989
8

Estimated expenditures by sport anglers and net economic values of salmon and steelhead for specified fisheries in the Pacific Northwest

Sorhus, Colin 16 December 1980 (has links)
Graduation date: 1981
9

Nutritional and environmental effects on triploid Atlantic salmon skeletal deformity, growth and smoltification

Smedley, Marie A. January 2016 (has links)
The Atlantic salmon (Salmo salar) is an iconic species that dominates the global finfish production sector with increasing market demand. The Scottish industry and government alone aspires for expansion of the sector to 210,000 t by 2020 with 154, 000 t produced in 2013. As such, there are pressures to improve sustainable development in particular to minimise the genetic impact of escapees on wild populations and reduce sea lice infection which are required for the granting of “green licenses” in Norway. The use of triploidy has been tested in the 1980’s with little success owing to suboptimal rearing conditions leading to elevated mortalities, poorer growth and a higher prevalence of deformities, in particular of the skeleton. Collectively: recent success of triploid trout farming, expansion to the salmon production sector and potential resulting pressure on wild stocks through escapee increases have reinstated interest to implement artificially induced triploid Atlantic salmon in commercial production. As diploid Atlantic salmon have undertaken extensive domestication to achieve the high quality production and welfare standards observed to date, triploid conspecifics too require husbandry optimisation to realise potential. In particular, industrialisation requires that higher observations of deformities and inconsistent growth trajectories during seawater ongrowing be resolved through optimisation of rearing regimes and subsequent standardization of husbandry protocols. Triploids possess additional genomic material and increased cell size yet reduced frequency that reflects known differences in physiology and supports that, in effect, triploids should be considered as a new species relative to diploid conspecifics. Therefore, this doctoral thesis aimed to study nutrition and temperature effects on triploid Atlantic salmon traits throughout the production cycle from ‘egg to plate’. Nutrition trials aimed to improve growth potential and mitigate skeletal deformities both in freshwater (FW) and saltwater (SW) whilst attempts were made to define a window of smoltification to ensure optimal ongrowing performance. Finally, impacts of embryonic temperature regimes that are known to impact long term performance and deformity development in triploids, were examined in relation to DNA regulation and yolk composition in an attempt to underpin potential mechanisms for the environmental impact of temperature on developmental phenotype. One of the main restrictions to triploid Atlantic salmon implementation is the increased prevalence and severity of skeletal deformities, particularly after the maring phase. The work performed in this thesis first demonstrated that protein and/or phosphorous (P) supplementation throughout SW ongrowing not only reduced the level of severely deformed (≥ 10 deformed vertebrae observable by x-radiography) individuals by 30 % but also sustained 6.8 % faster growth and improved harvest grade compared to triploids fed a standard grower diet (chapter 2). Comparison of x-radiography and severely deformed individuals between harvest and sea transfer highlighted that protein and P supplementation arrested deformity development whereas prevalence increased in triploids fed a standard grower diet. This implied that severe deformities were of FW origin and strongly suggest requirement for improved nutrition in FW to optimise SW performance. Therefore investigation of higher dietary P inclusion in FW was investigated and results showed significantly reduced number of deformed vertebrae and no severely deformed individuals in those fed 19.7 g total P Kg-1 compared with those fed 13.0 & 16.7 g total P Kg-1 (chapter 3). Most deformities were localised in the central (vertebrae 27 – 31) and caudal (vertebrae 52 – 57) regions for all treatments. However, triploids fed lower dietary P displayed a particular increase in prevalence within the tail region (vertebrae 32- 47) which is consistent with SW ongrowing reports and results from chapter 2, further highlighting FW origin of higher vertebral deformities reported in SW ongrowing in triploids. Higher P supplementation in FW also significantly improved growth in triploid parr compared to diploids and lower supplementation. However, this effect did not transpire in later FW smolt stages where weights were significantly higher in triploids fed lower compared to higher P supplementation. Expression of target genes involved in osteogenesis and bone P homeostasis in vertebrates were then analysed and a ploidy effect of osteogenic genes alp, igf1r and opn as well as a dietary effect on P homeostasis gene fgf23 was apparent in the parr stages but not smolt. In addition, stronger ploidy-diet effects were also observed in parr stages for whole body mineral concentrations. Collectively, growth, gene expression and whole body mineral content results indicate these earlier parr life stages may be more sensitive to P supplementation. This pronounced effect may be a consequence of seasonal accelerated growth associated with this period, where higher temperatures were also observed. The potential for shorter P supplementation windows in commercial production was addressed in chapter 4 with hope to cut economic cost to raw mineral inclusion in feed and also mitigate potential anthropogenic eutrophication on the environment that may be induced by P leached through uneaten feed and faeces. Triploids were fed higher dietary P (17.4 g total P Kg-1) until either early (5 g) or later (20 g) parr stages, or smolt (83 g) and monitored for performance throughout freshwater (FW) development. During later parr development (30 g), x-radiography assessment demonstrated that increased dietary P reduced the number of deformities and severely deformed individuals with no indication that feeding P for shorter windows improved skeletal integrity. Hence, P supplementation may be required throughout FW development for optimal skeletal performance. In addition, no differences in deformities were observed between triploid treatments at smolt. An effect of dietary P supplementation on whole body mineral concentration was observed in the early and later parr stages that was not as pronounced as smolt, which is consistent with results in chapter 3. Together, these results indicate that skeletal assessment during early developmental stages may not reflect smolt performance most likely as a consequence of seasonal effects of improved linear growth in the cooler winter temperatures prior to smolt where reversible deformities observed at parr may also be alleviated. In the same study (chapter 4), the inclusion of the probiotic Pediococcus acidilactici (Bactocell™) was also tested as a means to enhance gut assimilation as suggested in previous studies and therefore reduce the levels of P supplementation. Results clearly indicate superior skeletal performance in parr (30 g) as well as significantly less deformed vertebrae and no severely deformed individuals. However, at smolt (~83g), no effects of the dietary probiotic treatment were observed which may also be attributed to seasonal effects. Overall, nutritional research clearly indicate triploids require higher dietary P for optimal growth and skeletal development, which although is not consistent between life stages, is ultimately required throughout FW for optimal skeletal development at smolt. The use of probiotics offer a promising avenue for reduced P requirement in FW feed and further research should verify results and assess long-term performance. Timing of SW transfer according to correct parr-smolt transformation (PST) is essential for survival and growth performance in ongrowing where feeding and growth rate accelerate post-transfer. So far, SW transfer regimes and in particular the smoltification ‘window’ remains loosely defined in triploid Atlantic salmon and it is crucial that this be addressed to ensure optimal ongrowing survival and performance.
10

The fisheries of the Lower Columbia River, 1792 to 1850, based on EuroAmerican explorer and fur company accounts

Martin, Michael A. 10 August 2006 (has links)
The role of fish in the Native American economy of the lower Columbia River has never been considered in detail. My study focused on the Columbia River from its mouth to the Cascades and the Willamette River from its confluence with the Columbia to Willamette Falls. For this study I asked: How was salmon used? What other fish were important? Where and how were these fish taken and used? To address these questions, I evaluated historical documents, including explorer's accounts and the administrative records of fur companies dating from the late 1700's through the 1850's. I used fishery data, physical descriptions, migratory and spawning habits, and foraging patterns to identify fish in historic accounts. I annotated historic information and provided a synthesis of the historic fisheries. White sturgeon (Acipenser transmontanus), eulachon (Thaleichthys pacificus) and chinook salmon (Oncorhynchus tshawytscha) dominated the trade. Chum (O.keta) and lamprey (Lampetra sp.) were available, although not traded in large numbers. White sturgeon, eulachon, fall chinook, chum and lamprey were smoke cured. Steel head (0. mykiss) , coho (O.kisutch), perch (Embiotocidae), and resident trout were traded in small numbers indicating that other fish were part of the economy. Sockeye. salmon (O.nerka) was not traded. f "~{.' Indians captured white sturgeon with: multiple hooks on set-lines and funnel nets to take white sturgeon during the winter; scoop nets and the eulachon rake took eulachon; spring and summer chinook were taken with hoop nets and platforms in the Cascades rapids and at Willamette Falls; gaffs were used to take chinook and sturgeon during the summer in Baker Bay; and hoop nets took fall chinook in streams. Seine nets were noted but not were not discussed except for the chinook fishery of Baker Bay. Historic information on fishes used and methods of capture contrasts with the archaeological record of the Portland Basin. Resident freshwater fish, minnows (Cyprinidae) and suckers (Catostomus sp.), are abundant in the archaeological faunal record, but are rarely mentioned in historic accounts. Artifacts such as net weights are common in archaeological contexts in contrast with the limited discussions in the historic record. Possible explanations for these discrepancies are reviewed.

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