Thesis (Ph. D.)--University of California, San Diego, 1998. / Vita. Includes bibliographical references (p. 129-130).

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.

As concerns regarding the growing human population, rising seafood demand, and up to present limited success of fisheries management intensify, aquaculture is increasingly posited as a means to more efficiently produce seafood commodities. However, aquaculture expansion raises contentious issues itself. The current study addresses a number of these issues in attempts to improve hatchery production and related activities. Investigation of less-harmful chemotherapeutants for disease reduction at the egg stage could lead to improved hatchery microbial management, increased survival during early larval stages, increased efficacy of bacterial probiotic incorporation, and reductions in disease transfer between hatcheries and locations. Attempts to surface sterilize and disinfect cobia Rachycentron canadum eggs with 3 and 2% hydrogen peroxide solutions significantly reduced survival through the yolk-sac larvae stage. Furthermore, timing of treatment application at differing stages of egg development was found to significantly impact survival, highlighting the importance of this compounding factor. Bacterial probiotics can remediate water quality, reduce target host stress, and improve survival and population growth rates of live feed organisms. Two of the following studies investigated the benefits of incorporation of a Bacillus spp. probiotic blend in aquaculture activities. During closed container mock shipment of yellowfin tuna Thunnus albacares yolk-sac larvae, significant reductions in total ammonia nitrogen resultant from probiotic incorporation were observed. Furthermore, significantly reduced dissolved oxygen utilization might have resulted from stress reduction, as suggested by a non-significant lower degree in the breakdown of osmoregulation of the larvae. Incorporation of probiotics within rotifer Brachionus plicatilis cultures resulted in significantly higher daily mean populations, significantly lower population variability among replicates, and non-coincident logistic population growth regressions which yielded higher population growth rates and system carrying capacities. Broodstock management should not only maximize quantity of reproductive output, but quality as well. Significant increases in cobia egg diameter with increasing broodstock female age were detected, as well as significant increases in egg diameter with decreasing salinity. Confirmation of potentially increased larval growth rates resultant from increased energy stores of larger eggs when produced by older females, as demonstrated in other species, is warranted. Attempts to find production parameters which maximize cobia larval growth and survival would lead to increased sustainability via reducing demand for wild-collected Artemia and economic efficiency. Gaps in knowledge for achieving this goal continue to exist, but conclusions drawn from analysis of multiple production scale trials indicate temperatures of 29-31 °C maximize growth and survival. Improvement in sampling design and data analysis would increase statistical rigor and ease comparability of larvicultures outcomes across ranging influential factors. Further investigation of all of these matters is certainly warranted, although conclusions drawn could be effectively utilized to improve success of hatchery operations.

In this study, Gordon Schaefer Model is used to evaluate for the optimal conduction of open access and dynamic optimization in equilibrium condition. The results of the models are further analyzed by the method of comparative static analysis. According to the Schnute's method, the intrinsic growth rate, the catchability coefficient and the environmental carrying capacity have been estimated in the way to evaluate the equilibrium values of the resource stock and the effort of yellowfin tuna. The result of the sensitivity analysis is based on the assumption that all parameters are varied within reasonable ranges. The results of comparative static analysis consist with the results of the sensitivity analysis that the fishing is comparatively cohered with the dynamic optimization model. This study aims to provide a useful reference for the policy making in sustainable development of the offshore fishery resources in Taiwan.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 78-86). Also available on the World Wide Web.

Thesis (Ph. D.)--Memorial University of Newfoundland, 1998. / Includes bibliographical references (leaves 158-188).

Ninty three yellowfin tuna, Thunnus albacares, the fork length ranged from 80 to 168 cm were collected from the waters around Seychelles by two longline fishing vessels from April to December in 2006. The muscle and liver samples were analyzed for total mercury (THg) and organic mercury (OHg) concentrations.The concentrations of THg and OHg of the muscle were similar to previous studies. The concentrations of THg and OHg form the muscles and livers were positive-linearly regressed with the fish of Fork Length larger than 113 cm (big fish group), but only THg concentration of muscle was negative- linearly regressed 80- 112 cm (small fish group). Such patterns were first found in yellowfin tuna. It might be related to the ¡§growth rate¡¨ . Only one THg concentration of liver were over the standard set by the European Commission Decision (1 mg / kg THg wet wt.), other samples were in accordance with standard set by the European Commission Decision and the US-FDA food safty standard (1 mg / kg MeHg wet wt.). According to the dietary recommendations set by the Department of Health, Executive Yuan, yellowfin tuna can replace 86% animal protein source per week of people.

In this study, based on the basic theory model ¢wGordon-Schaefer model is used to discuss the equilibrium levels for yellowfin tuna in the Western and Central Pacific of open access (OA) and present value maximization (MPV). And then to compare the catches and the stocks on the two model¡¦s equilibrium value, the result shows the management of yellowfin tuna in the Western and Central Pacific tend to MPV model, the regional fisheries organization (RFMO) to detect the implementation of the measures (MCS) is significant; in addition, use sensitivity analysis and then to understand the changes on the stocks and the effort quantities effected by varying different parameters. In OA, if you want to get effectively maintain the sustainability of the stocks, should be considered to reduce the price and the catch coefficient, increase the cost per unit of effort to control; in MPV, we can understand that the catch coefficient and the intrinsic growth rate have a bigger influence in the effort quantities; Finally, by simulating the catches and the stocks, that if it can continue to effectively manage fishery by MCS in the future, the catches and the stocks of yellowfin tuna will tend to balance the value of MPV, and so on, not only resources effective use of maximum profit and maintaining our fleet of ocean-going business interests, but also resources can be sustainable.

The spatial movements of yellowfin tunas around the fish aggregating devices which were anchored below 40 meters water with a VEMCO VR2 receiver were investigated using ultrasonic telemetry tags V9P (VEMCO VP9-2H-S256). The experiment was conducted in the Shiao-Liu-Chiu Island of Taiwan from July to September, 2007. A pair of VEMCO VR2 receivers was separated by 400 meter distances in west of south sea ,Taiwan. A total of 9 tagged fishes with different sizes were monitored for maximum 19 days. Preliminary results showed that juvenile fish stayed longer and closer within FADs than the adult fish. Fish could move vertically to as low as 160 meters at daytime. They avoid the surface water where the temperature reach 30oC. In nighttime, juvenile fish that has fork length smaller than 55cm generally moves to the surface mixed layer. On the horizontal movement, there are three types. A) fish stays at FADs site. B) Fish move in and out FADs sites for a few hours period. C) fish moves away from FADs site for a long times (maybe 2~3 days). Sometimes juvenile fish would have B) or C) moved away from the FAD devices during dawn and dusk, and back at daytime. But this would not occurred with large fish. We estimated the attraction radius of FADs at least 1 km.

Tuna-dolphin-bird feeding assemblages are unique to the Eastern Tropical Pacific Ocean (ETP). These multiple species groups are believed to forage together in response to the physical properties of the near surface ocean as these constrain the distribution of prey. In the Galapagos Marine Reserve (GMR), intra-annual and interannual changes affect the properties of the water column, inducing mesoscale and fine scale temporal variability. Four three-week oceanographic surveys took place, in September 2008, April 2009, October 2009, and September 2010, between the coast of Ecuador and the Galapagos Islands and one small boat survey took place in June 2010 within the GMR. Marine mammal surveys were conducted during daylight hours and Conductivity, Temperature, Depth (CTD) sensor casts were taken throughout the survey. Data were analyzed to determine the types of water masses present and the strength and depth of the thermocline layer. These data were compared with the sightings of marine mammals, bird feeding groups, and tuna-dolphin-bird assemblages. Additionally, these data were used to predict where tuna would be likely to associate with dolphin groups. Results show Equatorial Surface Water was the dominant water mass throughout the archipelago, regardless of season or ENSO index. High salinity, cold water west of Isla Isabela indicated topographic upwelling of the Equatorial Undercurrent. Tropical Surface Waters from the Panama Current were detected north of the Equatorial Front to the east of the islands. Obvious changes in the water column properties were observed between El Niño and La Niña events in the GMR. Most mixed groups were sighted west and south of Isla Isabela during the four oceanographic surveys, as well as north and west of Isla San Cristobal in June 2010. Most sightings were in cool, high salinity waters, and high chlorophyll concentrations. There were a greater number of sightings during the April 2009 survey (ENSO-neutral conditions) than during any of the three fall surveys. Additionally, tuna-dolphin-bird groups were more likely to be seen near Isla Isabela, with the majority of them sighted during the April 2009 survey and a few sighted in each of the September 2008 and October 2009 surveys. No tuna-dolphin-bird groups were sighted during the September 2010 surveys. Results show that the presence and location of these multi-species groups may be controlled by the inter-annual cycles, the intra-annual cycles, or a combination of both types of changes seen within the Galapagos.