Graduation date: 1979

No description available.

Thesis (Ph. D.)--University of Rhode Island, 2003. / Typescript. Includes bibliographical references (leaves 240-271).

A heat stable protease was identified as the cause of textural degradation in cooked arrowtooth flounder (Atheresthes stomias) muscle. Maximum proteolytic activity in the fish muscle was observed between 55°C and 60°C and myosin heavy chain appeared to be the primary substrate for the enzyme. Degradation of this myofibrillar protein at 55°C was extremely rapid and myosin heavy chain was completely hydrolyzed to peptide fragments smaller than actin, while actin itself was unaffected. A single strand 32kD proteolytic enzyme was extracted from the muscle and purified 125-fold. The enzyme was stable to freezing for up to 6 months. Activity of the semi-purified enzyme at 55°C was optimal against casein between pH 6.0 and 7.0. Sulfhydryl reagents p-chloromercuriphenylsulfonic acid, iodoacetate, iodoacetamide and cystatin were effective in inhibiting enzyme activity in casein assays. The serine protease inhibitors phenylmethylsulfonylfluoride and trypsin-chymotrypsin inhibitor appeared to activate enzyme activity against casein. Adenosine triphosphate was also an activator. Arrowtooth flounder was then considered as a raw material for surimi, since the surimi process provides for repeated washing of the minced muscle and a final mixing step during which inhibitory substances can be conveniently added. Arrowtooth muscle was monitored at all stages of surimi production. There was no evidence of myosin degradation on sodium dodecyl sulphate polyacrylamide electrophoretic gels at any time during surimi production or during the preparation of samples for testing. However, when the washed mince was incubated at 55°C, 12% residual proteolytic activity was observed. This level was sufficient to degrade the myosin component of surimi gels prepared from the control surimi to which no inhibitors had been added. The food grade substances tested for proteolytic inhibition were bovine blood plasma powder, egg white powder, whey protein concentrate, carrageenan and crude α₂-macroglobulin. Addition of plasma and/or egg white powders to control surimi resulted in a product that was comparable to pollock in functional properties as measured by gel strength, expressible moisture and fold tests. Electrophoretic comparison of surimi made with 1.0% or 2.0% plasma powder or egg white with surimi produced with 0.1% or 0.2% α₂-macroglobulin suggested that the plasma and egg white contributed gel enhancing effects in addition to protease inhibition. Carrageenan was not effective as either a protease inhibitor or gel enhancer. / Graduation date: 1992

Thesis. 1978. Ph.D.--Massachusetts Institute of Technology. Dept. of Biology. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Vita. / Bibliography : leaves 137-151. / Ph.D.

The overall aim of this study was to gain a better understanding of the feeding mechanisms of the larvae and early juveniles of the sole, Dagetichthys marginatus (Soleidae), with which to assess the suitability of current feeding protocols and to facilitate the development of an appropriate pelleted feed. This was achieved by examining the ontogeny of the cranium of laboratory reared sole, with particular emphasis on those elements associated with feeding and by comparing the cranium of juvenile fish with that of adult fish. At 4 dah (days after hatch) Dagetichthys marginatus larvae develop the first rudimentary branchial arches that facilitates the capture and ingestion of food items. Subsequent development of cranial structures, such as the oral jaws, suspensorium, neurocranium, hyoid and branchial arches and the opercular apparatus enables the larvae, at 16 dah, to switch from ram feeding to suction feeding on live prey. The use of live Artemia nauplii from 4 to 16 dah is therefore appropriate. The first morphological asymmetries developed at 16 dah in the dentaries and at 22 dah the maxillae and the premaxillae began to show asymmetries. Teeth were present only on the blind side of the oral jaw elements and during this period (16 to 22 dah) the existing elements began to ossify. From 16 to 35 dah the standard feeding protocol consists of a combination of pelagic (Artemia metanauplii) and benthic prey (dead, frozen Artemia nauplii) and from 25 dah onwards a sinking pellet is provided. The time (dah) at which frozen Artemia and sinking pellets were provided, appropriately corresponded to the initiation of benthic feeding behaviour. However at this stage the use of pelagic Artemia metanauplii is inappropriate and unnecessary. At 31 dah the cranial morphology resembled that of adult fish. Adult D. marginatus display extreme asymmetries among the elements of the oral jaws, the suspensorium and certain elements of the neurocranium. Elements on the blind side are larger and more robust than those on the ocular side and are adapted for feeding, while those on the ocular side appear to have a respiratory function. From 31 dah the cranial elements are identical to those of adult fish, suggesting that no further feeding behavioural changes occurred and that a sinking pellet, of which the nutrient composition meets the requirements of the fish, would be appropriate for ongrowing.

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 228-246).

Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1985. / Vita. "October 1985." Includes bibliographical references (p. 135-142).

The white margined sole Synaptura marginata (Soleidae) was isolated as the most likely candidate for flatfish aquaculture in South Africa. The aim of the study was to screen the sole as a candidate aquaculture species by way of a comprehensive study of its biology and life history strategy and to identify possible "bottlenecks". The study was undertaken on the assumption that the biological data would provide valuable information for developing specific technologies that might be required for the farming of this species. Specimens were collected monthly by spearing along the Eastern Cape coast of South Africa between December 2000 and March 2002. Length-at-age data required for modeling the growth of S. marginata was obtained from sectioned otoliths. A Von Bertalanffy growth model with an absolute error structure best describes the growth for this species. The model parameters were: L∞ = 429.5 mm TL, K = 0.24 and t₀ = -1 .79 years. Analysis of gut contents showed that S. marginata feed exclusively on polychaete worms, mainly of the genus Morphysa. S. marginata shows a protracted summer spawning season of six months, from October to April. This was determined by the calculation of a monthly gonadosomatic index and a macroscopic maturity scale. Histological examination of the ovaries revealed five ovarian developmental stages. Size at 50% and 100% sexual maturity for females was calculated to be 235 mm TL and 300 mm TL (ca. 1.5 - 2.5 years of age) and all males> 154 mm TL were mature. S. marginata is a batch spawner, releasing a minimum of 3 batches of eggs per year. Relative fecundity is high (34000 eggs per year I kg) and this coupled with the protracted spawning season would make it possible to obtain adequate numbers of juveniles (for farming) for approximately five to six months of the year. Comparative analysis of the biological characteristics in relation to other soles farmed elsewhere in the world suggests that S. marginata is a suitable candidate for marine fish culture in South Africa.

Thesis (M.S.)--University of North Carolina at Wilmington, 2004. / Includes bibliographical references (leaves : 53-58).