Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 63-68). Also available on the World Wide Web.

Aspects of oxygen consumption and bioenergetics of the Atlantic halibut (Hippoglossus hippoglossus L. ) were studied under laboratory conditions. Resting oxygen consumption rate was monitored over 36 hour periods in Atlantic halibut while held individually in open system respirometers. Routine oxygen consumption rate was determined in small populations of tank held Atlantic halibut over 24 hour periods, through modification of tank systems as open system respirometers. Values for resting and routine oxygen consumption in this species were quantified and models Produced enabling the prediction of the energetic cost of homeostasis and spontaneousa ctivity for a range of fish size from 53g to 5861g, at temperatures of 6, 10 and 14°C. These results were ftirther used to form the basis of an energy budget equation for this species. PhotoPeriod influences on the periodicity of respiratory rhythm in both resting and routine oxygen consumption trials were determined through analysis of data recorded throughout the 24 hour daily period. The results indicated a cyclic respiratory rhythm, with peak oxygen consumption often observed nocturnally. The relevance of these results to culture of this organism are discussed. Post-prandial oxygen consumption and ammonia excretion were measured in small populations of tank held Atlantic halibut, these results contributing further information to the partitioning of energy within the metabolic and excretory components of the energy budget equation. Values for resting, routine and postprandial oxygen consumption in the Atlantic halibut were found to be low in comparison to roundfish species, but corresponded closely with literature data produced for other species of temperate marine flatfish. Activity patterns in small populations of Atlantic halibut were monitored over 24 hour periods in a specially constructed film unit. The results of this work showed dualistic patterns of activity over the diurnal cycle. Further elucidation of the energy budget was achieved through the determination of the metabolic costs of activity in the tank environment. Atlantic halibut were observed to remain at rest for periods of between 76% and 94% of any 24 hour period, with the time at rest dependent on fish size and stocking density. One 28 day trial was undertaken in which the components of the energy budget were measured simultaneously, and the balance of the budget investigated. Oxygen consumption, ammonia excretion, growth, feed consumption and faecal production were monitored within a purpose built experimental unit, and these values finther applied to the construction of an energy budget model. Finally, the oxygen consumption data of this study was ftirther applied to produce a model quantifying the water requirements of this species in a single-pass tank system, for the intensive culture of this species in the tank environment. Further development of these figures allowed the quantification of the pumping costs in an Atlantic halibut ongrowing tank system, and these figures were incorporated into a simple economic model. The results present some of the first bioenergetic data produced for this species, and this is an important step towards the development of an Atlantic halibut farming industry.

Thesis (M.A.I.S.)--Oregon State University, 1997. / Typescript (photocopy). Includes bibliographical references (leaves 99-107). Also available online.

Thesis (M.Sc.)--Memorial University of Newfoundland, 1999. / Restricted until November 2000. Bibliography: leaves 107-118.

The quality of radiation-pasteurized halibut stored at 34°F was evaluated subjectively and objectively over a period of 18 weeks. Results of flavor evaluation and chemical analyses showed that the storage life of halibut irradiated at 0.50, 0.75 and 1.00 megarad was extended more than threefold. Although irradiated samples were consistently rated inferior to unirradiated reference sample by the taste panel, they remained in good condition throughout the 18-week period. No viable, aerobic microorganisms were found. Very little increase in trimethylamine nitrogen, volatile acid number and pH was observed. An increase in free amino nitrogen content was noted on the ninth week up to the twelfth week of storage after which a slight decrease was evident. Pasteurizing radiation was found to induce oxidative rancidity in ground halibut as determined by TBA number and peroxide value. Discoloration of the fish or rusting was observed in all irradiated samples except those treated with 0.005 percent of a commercial mixture of antioxidants, Tenox VI. Oxidative rancidity as measured by TBA number and peroxide value was also markedly inhibited by Tenox VI. Thiodipropionic acid used at the same concentration was found ineffective in preventing rancidity and rusting in the irradiated fish. / Graduation date: 1964

This study examines the spatial evolution of the Eastern Pacific halibut fishery over the period 1888-1972 in terms of resource exploitation and vessel-port interaction and attempts to delineate the factors which brought about the observed patterns. Four distinct stages of development are identified: (1) a stage of spatial confinement and resource depletion characterized by corporate involvement and restricted vessel range, (2) a stage of spatial extension, company fleet decline, and independent fleet expansion, (3) a stage of spatial adjustment, quota control, and extreme competition, (4) a stage of further spatial extension, fleet decline, and maximum sustained yields. The spatial structure of the industry at each stage of development is shown to be a function of resource availability, fishing costs, and changes in halibut fleet behavior. The time-cost-distance factor between producing grounds and the landing/processing sector of the industry proved to be a critical factor in a fishery that was characterized by increased competition for annual quotas. Conceptual models of the industry's spatial structure have been developed to portray the major changes which occurred from one stage to the next. These in turn are further developed to conceptualize the evolution of the halibut fishery over the 1888-1972 period. / Arts, Faculty of / Geography, Department of / Graduate

Growth rates between individually tagged Atlantic halibut, from a single batch of farm produced eggs, on-grown in sea cages and pump ashore tanks for three years were significantly different. The tank reared fish 405g - 5992g showed a 29% premium in growth (final weight) compared to the cage reared fish 444g -4640g. Females in both systems reached a greater size (7352g tanks, 5836g cages) than males. Males that matured early (3819g tanks, 2877g cages) had a lower mean end weight than males maturing a year later (4326g tanks, 3086g cages). Early maturing males had the largest initial size. Seasonal variations in growth were observed for all groups. Major divergences in growth between males and females only became apparent when the males first matured at around 1.5 - 2 kg. No female maturation was observed during the trial. Halibut growth was determined to be positively allometric with growth of males being more linear then females. Condition factor increased with time whilst there was a decrease in Specific Growth Rate (SGR) from approximately 0.5%day⁻¹ to 0.1%day⁻¹ throughout the trial. Concentrations of plasma cortisol, osmolality, chloride and glucose measured through the trial provided no evidence of chronic stress at either site. Acute confinement stress (2, 12 and 30 minutes) was shown to elicit both primary and secondary stress responses in accordance with other marine teleosts. Increases in plasma cortisol, osmolality, CI⁻, Na⁺ and glucose were observed, reaching maximum concentrations within 80 minutes, although there was no effect on plasma K⁺. The duration of the confinement appeared to have no effect on the magnitude of the response. Following repeat confinements (4 days later) there was no evidence of either habituation or a cumulative effect in terms of cortisol or glucose whereas the effects on osmoregulatory function (Na⁺, CI⁻ and osmolality) appeared to be longer lasting. The results provided the first information regarding the stress response of the Atlantic halibut and enabled a better interpretation of the vales measured in the fish reared in tanks and cages (chapter 1). In vitro cortisol production (% above basal secretion), measured by radioimmunoassay, from perifused interrenal tissue of the Atlantic halibut was significantly stimulated by porcine adrenocorticotrophic hormone (ACTH) (0.01-1.0 μM) and [Asn¹, Val⁵] angiotensin II (All) (0.1-lO μm). No significant increase in cortisol production resulted from physiological levels of potassium (K⁺) although non-physiological levels (lOmMKl) did elicit a mild response in comparison to the effects of ACTH and All. Maximum steroid production was in response to 0.01μM ACTH (1351% above basal secretion) and 1.0μM All (397% above basal secretion). With increased concentrations above these levels of both ACTH and All there was a reduction in the degree of cortisol stimulation. The results show that the interrenal tissue of the Atlantic halibut responds in accordance to that of other teleosts to classical steroidogenic peptides.

The Atlantic halibut (Hippoglossus hippoglossus) was selected as a new aquaculture candidate towards diversification from salmonid culture. The species was chosen because of its high market value and perceived good growth in the cold waters of the target farming regions. Extensive and collaborative research efforts formed the basis for the culture of this benthic marine species. Broodstock populations were established from a limited number of wild individuals due to the high costs involved in their capture. First generation hatchery reared offspring are now being selected as replacements but with no knowledge of a broodstock replacement strategy to manage this valuable genetic resource and to maximize the potential of this species the industry runs the risk of genetic degradation with the associated problems of inbreeding depression. This thesis investigates the processes involved with developing a genetic management strategy, using genetic profile technology, based on a population in Scotland at Otter Ferry Seafish Ltd. The level of genetic variability of 70 individuals in the parental population and 802 of their offspring (F1) in two year classes (1995 and 1998) was assessed at 7 microsatellite loci. The parental population which was comprised of three different stocks was genetically diverse, however, when compared with their offspring, substantial reductions in genetic variation, as judged by allelic diversity, were observed. The parentage of these F1 individuals was determined by exclusion principles and 91% of all the offspring genotyped were unambiguously assigned to a single parental pair. The assignment revealed that only half of the parents succeeded in contributing to the F1 generation. This problem was compounded by the fact that the family sizes were highly skewed such that the entire population consisted of a small number of large families resulting in an unacceptably low effective population size of 8.11. The inbreeding coefficient in the F1 generation was 6.16% however this differed markedly between the 1995 (7.74%) and 1998 (10.64%) year classes. The repeatability of reproductive performance defined by five performance traits reflecting quantity and quality of eggs, frequency of stripping events and viability was assessed by REML using data collected over three spawning seasons from 239 F1 females. The phenotypic correlations obtained between quality and quantity traits were low in magnitude and the study showed that with the exception of seasonal activity, all traits studied improved with age. There was also an effect of photoperiod in that fish kept under a 4 month-delayed regime did not perform as well as the fish under a one-month extended regime. Of all five traits, only volume of eggs collected was repeatable (r=0.37±0.07). This suggests that it is the only reproductive character influenced by the fish and all other traits, especially those pertaining to egg quality are determined by management practices. The heritability of body weight at four stages in the growout phase of production was estimated by REML using data from 486 F1 individuals. These animals were reared in two different sites, a land based tank and a sea cage. Significant effects of site, sex and grade were observed and by the end of the trial the average weight of fish in land based system was higher by 2 kg. Females were over 3 kg heavier than males and this difference was attributed to precocious maturation while fish in the smaller grade were consistently though decreasingly lighter than their larger counterparts. Heritabilities, derived from sire, dam and combined estimates ranged from 0.09 to 0.53 with wide confidence intervals. The poor precision of the estimates was due to the highly imbalanced family structure and the small number of offspring studied. Values varied depending on the age of fish and the source of variance used to estimate them. Heritabilities increased with age and although sire estimates were higher than dam estimates these differences were tested and the results obtained consistent with the conclusion that they represent nothing more than chance. The results suggested that selection for increased body weight in the halibut was likely to be successful. Based on the findings of the study a genetic management strategy for the Atlantic halibut was proposed structured on controlling the rate of inbreeding and a theory of domestication. The need to introduce additional individuals into the population was strongly recommended.

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Thesis (M.S.) in Marine Bio-Resources--University of Maine, 2006. / Includes vita. Includes bibliographical references (leaves 73-81).