Thesis--University of Washington. / Vita. Another copy has number: Thesis 27740. Bibliography: leaves [167]-182.

Commercial capture-based aquaculture of the Atlantic bluefin tuna (ABT), Thunnus thynnus (L.), has been prominent in the Mediterranean for over a decade. Owing to several limitations encountered in working with the species, including its high commercial value, there has been little research carried out relating to this species. The objective of this study was to examine several health parameters of captive ABT. These included an examination of coronary artery lesions, haematology, plasma biochemistry, assessment of immune function and changes in fatty acid (FA) flesh content through the on-growing period. Arteriosclerosis in fish is a pathologic condition of uncertain etiology and involves the main coronary artery in teleosts. Apart from reports of their widespread occurrence in salmonids, they have been described from a restricted number of wild ABT specimens but have not received further attention. This investigation analysed the effect of size and period of net-pen rearing on the prevalence and severity of arteriosclerotic lesions in ABT. Coronary arteries from wild and captive fish were investigated and prevalence was 100 %, but increasing structural degradation was observed with increasing fish size, suggesting that lesions progress throughout the life of the fish. Due to the limited availability of wild specimens, the effect of captivity on arteriosclerosis in ABT could not be adequately quantified, although observations suggest that the farming process has no major effect on arteriosclerotic lesions in ABT. Studies on the haematology, plasma biochemistry and immunology of ABT are limited. Haematological and plasma biochemical indices are useful in animal health assessment but use of these requires the establishment of species-specific ranges. Blood was collected from captive ABT specimens of varying weight (61-361 kg) and the major haematological (n = 45), plasma biochemical (n = 30) and immunological parameters (n = 45) were quantified. Size-based differences were found in haematological indices between experimental sub-groups including increased erythrocyte number and haemoglobin level in smaller ABT. No differences were found in immunological parameters except for total IgM levels, which were higher in the smaller individuals. Preliminary investigations indicated that disease prevalence in captive ABT is very low. Epidermal mucus is an important interface between fish and their environment and comprises immunological components which act as a first barrier against pathogen entry or colonisation. Mucus was collected from captive ABT and analysed for innate immune components. The presence of IgM was detected in the mucus of ABT by an enzyme-linked immunosorbent assay and several different enzymes were detected with an API-ZYM kit assay. Zymography experiments confirmed the presence of protease-like enzymes in the mucus, while enzyme assays quantified alkaline phosphatase, protease, esterase and cathepsin B activities. Lysozyme levels were high. The mucus agglutinated sheep erythrocytes but did not demonstrate complement or bacteriolytic activity. There is restricted information on the fatty acid composition of farmed ABT or how this is influenced when the fish are held under commercial aquaculture conditions. This study investigated the FA composition of farmed ABT, its variation by dorsal muscle region and the correlation between dietary FA composition with that of the fish. Analysis of flesh samples retrieved from farmed ABT did not reveal significant differences in the FA composition of experimental sub-groups irrespective of size, time held in captivity or diet. These results indicate that FA metabolism in ABT is substrate-selective. Gene expression measurements from several organs of ABT showed that expression of Δfad5 and elovl5, genes involved in FA metabolism, were highest in the brain followed by the liver but no expression of these genes was detected in the spleen. The findings of this research address aspects of health evaluation and nutritional status in farmed ABT and are discussed in terms of farming practice. Conclusions from some of these studies suggest that the practice of holding wild-captured stock in cages for periods of up to 18 months does not result in significant impact on ABT.

Photocopy of typescript. / Bibliography: leaves 107-114. / ix, 114 leaves, bound ill. 28 cm

Thesis (M.Sc.)--Macquarie University, School of Biological Sciences, 1982. / "June 1981" Bibliography: leaves 176-185.

Thesis (M.A.) -- Central Connecticut State University, 2007. / Thesis advisor: Cheryl Watson. "... in partial fulfillment of the requirements for the degree of Master of Arts in Biomolecular Sciences." Includes bibliographical references (leaf 38). Also available via the World Wide Web.

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 64-69). Also available on the World Wide Web.

Thesis (M.Sc.) -- Memorial University of Newfoundland. / Typescript. Bibliography : leaves 189-212. Also available online.

Thesis (Ph.D.) -- University of Rhode Island, 2009. / Typescript. Includes bibliographical references (leaves 280-295).

This thesis evaluates the utility of a sport fishery for yellowfin tuna, Thunnus albacares, in the Pemba Channel, Kenya, in providing ecological information relevant to commercial fishery assessment and management. Age, growth, reproductive status and diet are measured, together with an innovative assessment of the Indian Ocean yellowfin tuna stock. Catch/effort and weight data from the records of the sport fishery from 1963-1995 demonstrate a decline in tuna mean weight since the advent of purse seining in 1984. A periodicity of 5-6 years was detected in the Indian ocean longline fishery catches, and in the sport fishery catch/effort and mean weights. Samples were taken from tuna caught in the sport fishery from 1981-88. Sport-fished samples were more random in size, age and sex (ratio = 1: 1) than catches from any of the three major commercial fisheries. The total mortality rate of cohorts deconvoluted from weight-frequencies in the sport fishery catch over 6 years was used in a Caddy & Csirke analysis. Maximum Sustainable Yield estimates of the Indian Ocean stock were 113,000 tonnes (new method), 110-160,000 tonnes (Walters' method); compared with only 40-52,000 tonnes using the standard equilibrium method. Tuna (1653 over 7 years) were successfully aged using length frequency analysis and by a novel method based on clusters from a Principal Components Analysis of morphometric measures. Juvenile growth was fast, 3.1 cm/month, whereas adults grew at about 2 cm/month. Gonads (>1500) were staged for 5 years and histologically examined for 2 years. Female yellowfin mature earlier than males, but males become ripe earlier in the season. The spawning stock consists of females >120 cm FL. Diet was scored over 4 years and evaluated volumetrically over 2 years. Juvenile tuna eat fish, but adults opportunistically consume fish, cephalopods and crabs, depending on availability. Catchability by gear in both the sport and commercial fisheries is likely influenced by the currently abundant food.

No description available.