Thesis (M.S.)--University of Delaware, 2006. / Principal faculty advisor: Willett Kempton, Dept. of Marine and Earth Sciences. Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (p. 281-297).

Thesis (Ph. D.)--University of Rhode Island, 2005. / Typescript. Includes bibliographical references (leaves 186-195).

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

Thesis (M.S.)--University of Wisconsin--Stevens Point, 2009. / Submitted in partial fulfillment of the requirements of the degree Master of Science in Natural Resources (Fisheries), College of Natural Resources. Includes bibliographical references.

Prior to 2010, megrim in the northern North Sea was not considered in the annual stock assessment for the species on the Northern Shelf. The underlying aim of this study was to fill some of the current knowledge gaps in megrim biology and ecology in the northern North Sea, providing improved scientific information that is intended to assist in the development of an informed assessment of the stock in future years. Changes in the distribution and relative abundance of common megrim Lepidorhombus whiffiagonis in the North Sea were investigated by comparing three data sources: fishers' knowledge collected through a structured questionnaire; a vessel's haul-by-haul catch data from the personal diaries of a single skipper over a 10-year time-series, and catch rates from fishery-independent surveys (IBTS Q1 and Q3). A number of life history characteristics of the common megrim Lepidorhombus whiffiagonis (Walbaum) were compared between the northern North Sea and Rockall, the latitudinal extremes of the species' distribution on the Northern Shelf. An estimation of the potential and relative fecundity of L. whiffiagonis was also presented for the first time. Furthermore, genetic analyses of adult megrims captured on the Northern Shelf were used to determine whether there was evidence of separate populations on the northern Shelf, the geographic distributions of any separate populations and whether the evidence from this genetic study supports the management units implemented in 2011. Finally, temporal variation in megrim discarding in the mixed demersal fishery in the northern North Sea prior to, and following recent quota increases was investigated. Logistic regression models were applied to investigate the effects of a range of explanatory factors on the probability of individual fish being discarded.

Fish meals, particularly British Columbia herring meals, and condensed herring solubles have been studied for their nutritive properties as supplements in poultry rations. Both commercially and experimentally prepared herring meals were used in the study. Protein quality in fish meals was investigated to ascertain what degree of variability exists in commercial samples and to obtain information regarding the effects of raw material, processing temperature and storage. On the basis of the Protein Index Values commercial fish meals appeared to vary in the quality of their protein content. Much of the variability amongst different meals could be ascribed to the nature of the raw material. Experiments were carried out in which herring meals prepared under controlled conditions from material of known origin were compared. It was shown that the value as a protein source for the growing chick of meals produced under a considerable range of drying temperatures was similar. Differences in the vitamin content of fish meal were found to be responsible for differences in the rates of growth of chicks fed herring meals which had been dried at high and low temperatures. With the basal rations employed, folic acid was the limiting nutrient when herring meal was used as the sole source of supplementary protein. The folic acid content of meals prepared from similar raw material was found to be markedly affected by the temperature at which the meals were dried. Chicks and poults fed rations formulated to be complete in the known nutrients grew at a faster rate when 2.5 to 5.0 percent of herring meal was added to the rations. It was concluded that herring meal contains a factor(s) not identified with any of the known vitamins. Condensed herring solubles was shown to be an effective vitamin supplement to practical type poult rations whether or not the ration contained herring meal. Extraction of the oil from herring meals did not improve the growth response of chicks to the use of the meals as protein supplements. Normal and extracted commercial flame-dried meal and experimentally prepared low-temperature-dried meal were compared in this regard. Storage of herring meals for one year at -25°, 21° and 37°, respectively, did not appear to affect the nutritive value of the meals as protein supplements for chick rations. Chemical changes did occur in the fat present in herring meals during storage. The amount of ether-soluble material decreased with the length of the storage period and the iodine value of the ether extract decreased. The addition to the meal of 0.15 percent butylated hydroxytoluene before storage prevented any decrease in ether extractability of the fat during a 9-month storage period and considerably reduced the drop in iodine value of the extract. / Land and Food Systems, Faculty of / Graduate

Certain compounds having the "carbonyl enediol" structure ( Formula omitted) , and also sodium chloride, were studied for use in glazes for frozen whole dressed fish. Incorporation of these compounds caused, in general, formation of thicker, glazes on the fish than did water alone and the glazes so formed were relatively non-cracking. The cyclic compounds, reductinic acid (in concentration 0.6475% or 0.00568M), and 1-ascorbic acid (1.0% or 0.00568M), afforded satisfactory protection against oxidative rancidity for periods of the order of 5 to 6 months. On the other hand, the acyclic compounds, reductone (0.5% or 0.00568M), diammonium dihydroxymaleate (0.518% or 0.00568M), dihydroxy maleic acid (0.84% or 0.00568M), gave comparatively poor protection. Sodium chloride (2.0%) gave about the same protection as water alone. The antioxidants probably protect the fish against oxidative rancidity by rendering atmospheric oxygen unavailable to the indigenous fats. / Science, Faculty of / Zoology, Department of / Graduate

The thesis deals with the use of a dilatometer in studying some of the physico-chemical phenomena occurring in fresh fish flesh when subjected to freezing at temperatures ranging from 0° C to -30° C. Two different kinds of fish flesh, marine lingcod (Ophiodon elongatus) and fresh water rainbow trout (Salmo gairdnerii) were used for comparison. True freezing point determinations of samples of fresh flesh cut from the above species of fish were made and found to be the same, viz, -1.5°C (29.1°F.). The percentage of water removed as ice at varying temperatures below the initial freezing point were calculated by necessary adjustments of experimentally determined values. A permanent net decrease in volume accompanying freezing and thawing of the samples of flesh was observed and measured. This change in volume is probably due to the denaturation of the protine, and was found to be 0.075%. The coefficient of cubical expansion (∝) of anhydrous fish muscle was measured for the first time and found to have the average value of 0.000118 over a temperature range from -30°C. to +20°C. / Science, Faculty of / Zoology, Department of / Graduate

No description available.