Thesis (Ph.D.)--Murdoch University, 2005. / Thesis submitted to the Division of Science and Engineering. Bibliography: leaves 170-197.

Thesis (M.S.) Natural Resources (Fisheries), University of Wisconsin--Stevens Point, 2004. / Includes bibliographical references (leaves 108-116).

Thesis (M.S.)--Humboldt State University, 2006. / Includes bibliographical references (leaves 45-50). Also available via Humboldt Digital Scholar.

Thesis (M.S.)--Oregon State University, 2011. / Printout. Includes bibliographical references (leaves 60-67). Also available on the World Wide Web.

The processes influencing larval fish survival in the low-latitude open ocean are poorly understood, especially with regard to feeding. As part of a large-scale study that included two years of monthly sampling in the Straits of Florida (SOF), the objectives of this dissertation were to elucidate the larval fish feeding behaviors and strategies of 1) istiophorid billfishes, 2) tunas, and 3) coral reef fishes, while also 4) characterizing the feeding environment, synthesizing the dominant trophic pathways to fish larvae, and reviewing the literature for evidence of latitudinal distinctions in larval fish trophodynamics. Larval billfishes exhibited highly selective feeding, and their diets were numerically dominated (90%) by two genera of crustaceans, Farranula copepods and Evadne cladocerans. These prey were consumed throughout early larval ontogeny, from first-feeding through piscivorous lengths (> 5 mm), until piscivory became exclusive near 12 mm. High feeding incidence (0.94) and rapid digestion (~3.5 hrs) suggests frequent and successful feeding by billfish larvae. For tunas, nearly all larvae examined (>98%) contained prey. Thunnus spp. exhibited a mixed diet, while skipjack, little tunny, and Auxis spp. nearly exclusively consumed appendicularians. All four tuna taxa co-occurred in the western SOF where prey was more abundant, while in the central and eastern SOF (where prey availability was lower), only Thunnus spp. and skipjack were present. Additionally, these two taxa exhibited significantly different vertical distributions. Estimates of predatory impact indicated the potential for depletion of resources in the absence of the spatial and dietary niches of larval tunas. Coral reef fish families examined included Serranidae, Lutjanidae, Mullidae, Pomacentridae, Labridae, Scaridae, and Acanthuridae. Feeding incidences were high (0.94 to 1.0) for all taxa except scarids (0.04), and diets were narrow and predator-specific. Cluster analysis yielded clear groupings based on the selective feeding exhibited by the taxa, while within taxa, canonical correspondence analysis illustrated the change in diet with a variety of variables. The physical and biological environment varied markedly across the SOF, largely influenced by the Florida Current. Characteristics examined included thermocline depth, fluorescence, and abundances of total plankton and copepod nauplii. The feeding ecologies of the 21 taxa of fish larvae in this work were synthesized into qualitative and quantitative webs that illustrate the variable trophodynamic strategies of larvae in the SOF and the levels of community reliance upon zooplankton prey types. A review of 170 investigations on larval fish feeding revealed notable distinctions between high- and low-latitude regions, highlighting the substantial variability across environments in the role of larval fishes within the planktonic food web.

Fish and fish waste can be used to produce various value added by products such as proteins, oil, omega-3 fatty acids, biodiesel, amino acids, peptides, collagen, gelatin and silage, each of which has various applications in the food industry, renewable energy and medicinal purposes. Fish protein contains amino acids and many bioactive peptides . Fish proteins are found in the flesh, head, frames, fin, tail, skin and guts in varying quantities. After removing the flesh, all other parts are considered waste which is not properly utilized. The aim of this study was to evaluate the enzymatic extraction of amino acids from fish protein for use as substrates in the microbial production of jadomycin, an antimicrobial agent and potential anti-cancer drug. In this study, enzymatic extraction of proteins was carried out using Alcalase enzyme at three enzyme concentrations (0.5, 1 or 2%) and four time intervals (1, 2, 3 and 4 h). The fish protein hydrolysate was dried using spray dryer to obtain protein powder. The highest protein yield (76.30% from whole fish and 74.53% from the frame) was obtained using 2.0% enzyme concentration after 4 h of hydrolysis. The enzymatic extraction of amino acids were carried out using the enzymes Alcalase and Neutrase (individually and in combination) and the effect of reaction time (24 and 48 h) on the hydrolysis of proteins was studied. The profiling of amino acids was carried out using gas chromatography. Fourteen amino acids were extracted from fish proteins of which twelve amino acids have been used by researchers for the production of jadomycins. These are: alanine (7.59%), glycine (5.82%), histidine (3.59%), isoleucine (5.30%), leucine (9%), lysine (7.34%) methionine (2.2%), phenylalanine (4.2%), serine (4.3%), threonine (5.40%), tyrosine (3.17%) and valine (7.2%). Tryptophan which is suitable of producing jadomycin was not present in the fish protein. No reports were found in the literature for jadomycin production from glutamic acid. Therefore, glutamic acid (9.85%), and proline (0.98%) which are present in the fish protein should be investigated for possible production of jadomycins.

Theoretical part of the master thesis deals with the occurrence of different mercury species in the environment and describes analytical methods used for determination of mercury in biological samples. In practical part of the master thesis mercury concentration in 14 samples of selected fish and fish product was determined using single purpose absorption spectrometer AMA 254. Measured results were statistically processed and consulted with EU legislative norm.

Murray cod Maccullochella peelii peelii is an iconic freshwater angling species that has suffered declines in abundance and is now listed as a nationally vulnerable species. Despite recognition of the need for biological knowledge to provide future management directions, little is known of its ecology. This thesis examines that ecology to provide new knowledge and recommendations for improved conservation management. (For complete abstract open document)