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This thesis presents an assessment concerning the potential of horizontally integrated aquaculture, with outcomes assessed from a systems-based perspective. A literature review concerning the negative impacts and the limitations of current wastewater management approaches demonstrated that improved strategies are required. Horizontally integrated aquaculture was proposed, where the productive reuse of aquaculture wastewater ameliorates associated negative impacts. A definition for horizontally integrated aquaculture is presented and management strategies that conform to this definition reviewed. The development and application of the ADEPT bioeconornic model to assess the potential of a constructed wetland and trout fishery to treat wastewater from a commercial smolt unit in Scotland is described. The model outputs were tested against observations from commercial facilities operating under comparable conditions to those envisaged for horizontally integrated systems. Findings demonstrated that the modelling approach adopted was generally effective in predicting the composition of wastewater outputs from the farm and the effect of the selected treatment strategies. The model was applied to two further case studies. One assessed the potential of treating wastewater from shrimp farms in Thailand using a constructed mangrove wetland; the second evaluated the possible advantages of a rational design approach to lagoon-based wastewater treatment and reuse, as opposed to a conventional design and traditional practices developed in peri-urban Calcutta.

This thesis addresses questions of identity and ontological legitimacywithin the commercial shark fishing community of Bass Strait,Australia. I consider the implications of competing discourses for theintegrity of fisher identity, environmental conservation and publicnarratives on environmental ‘crises’. I draw upon ethnographic materialdeveloped with commercial fishers and, to a lesser extent, fisheries‘experts’, to explore ambiguities in understandings of individuality andperceptions of the marine environment. Informing this analysis aretheories of practice, particularly notions of embodied relationships andknowledge, the role of ‘luck’ in enabling a particular expression of‘individuality’, the ‘skipper effect’, a consideration of nation-statesanctioned and popular media representations of the environment, andthe peculiarly Australian experience and representation of individuality,both as performance and as trope. These themes are consideredagainst a backdrop of the physical and social activities involved incommercial fishing, and the 2001 nation-state-initiated introduction ofan Individual Transferable Quota management system.

During the period April 1994 and February 1996 as part of an investigation into the national Iinefishery, the east coast shore fishery and the recreational and commercial ski-boat fisheries were surveyed, at eight sites between Kei Mouth in the East and Stil Bay in the West. Roving creel, access point and aerial surveys were used. A questionnaire was developed for each sector to gather data on catch and effort, fisher demographics, economics, fisher attitudes towards, and knowledge of, the current management regulations and assess the efficacy of the fisheries inspectorate. During the access point survey the catch of 3273 fishers was inspected and 1556 interviews were conducted. Questionnaires were conducted on 118 recreational ski-boaters and the catch of 165 boats was inspected. 96 commercial skippers were interviewed and 230 had their catch inspected. Three aerial surveys of the entire area were conducted during which a total of 1067 shore fishers were counted giving a shore fisher density of 0.39 fishers.km⁻¹. The majority (99%) of participants in all sectors of the linefishery were male. The greatest number of participants were white, shore fishery 77% recreational ski-boat 98% commercial skiboat 89%, followed by coloured, asian and black people. To a large extent this reflects the income of various racial groups. Most fishers supported the current linefish management plan. However, when tested on their knowledge of the size limits, bag limits and closed seasons of their target species many shore fishers (59%) did not know them and a high proportion of fishers in all sectors had disobeyed at least one of the regulations (shore 50%, recreational ski-boat 70%, commercial ski-boat 56%). When compared to historical data the present catch per unit effort (CPUE) in all sectors has decreased. Most interviewees in the various sectors did not accept responsibility for the decline in CPUE, but attributed it to three principal reasons vis their perceived direct competitors, trawling and pollution. Analysis of the catch revealed that all sectors were multispecies fisheries, with each sector being characterised by a small number of target species. Catch composition differed significantly between the shore and ski-boat sectors, but there was significant overlap between the two skiboat sectors. Analysis of the catch in comparison to that reported to the National Marine Linefish System (NMLS) revealed that there was a substantial degree of under-reporting. There was little seasonal difference in effort in the shore fishery while the recreational ski-boat effort was highest in the summer and the commercial ski-boat effort was high in the winter. Effort in the shore and recreational ski-boat fisheries was concentrated over weekends while the commercial ski-boat effort was highest during weekdays. Total effort for the entire area was estimated at 903 186 (±1913) fisher days per annum in the shore fishery, 24 357 (±685) recreational ski-boat fisher days and 64 266 (±1686) commercial ski-boat fisher days. Expenditure and capital investment in the various sectors was calculated, as were earnings of the participants in the commercial ski-boat sector. The linefishery in the Eastern Cape was estimated to have a minimum capital investment in excess of R210 million and more than R32 million is spent annually on running costs. The commercial ski-boat fishery directly employed an estimated 3184 people. The economic implications of changes in CPUE for the commercial ski-boat fishery are considered, as are the benefits of a recreational angling licence. Management of the linefishery is discussed in relation to the findings of this study.

This study investigates key decision-makers' perceptions of sustainable sea fisheries in Namibia, and explores the possibilities for the future development of education programmes that focus on "sustainability" in the fisheries sector. The concept of "sustainability" and its application in the context of a biological resource, namely sea fisheries, was examined. A series of questions were raised concerning sustainable fisheries: intergenerational implications of patterns of resource use, equity concerns, time horizons, and the protection of marine biodiveristy, among others. Examples from the Namibian and the European Community Sea Fisheries Industries are used to illustrate these issues. In spite of divergent views on what "sustainability" means, the study leads to certain findings that have broader policy implications. Data was collected from semi-structured interviews undertaken with six (6) key decision-makers in the Sea Fisheries Industry of Namibia, then analysed and assessed. The perceptions of key decisionmakers were determined by qualitative analysis in the interpretive paradigm. The data indicated some agreement in terms of what the key decision-makers think about the sustainable utilisation of the fisherjes resources. It is almost impossible to have complete agreement, because the decision-makers are from different contextual backgrounds. Those who make the decisions are more concerned about "how to manage" and those who act on the decisions put more emphasis on economic self-interest. Although the interviewees' perceptions of sustainable fisheries was imperfect, there was broad support for its aims and principles. The study also revealed that the achievement of sustainable sea fisheries development in Wamibia will require broader educational and public awareness programmes to enhance participation in decision-making debates. Formal and informal marine environmental education, from the perspective of "Responsible Fishing" has been emphasised.

Target species in some Australian shark fisheries are adequately managed, but there has been little attention given to non - target shark species and there is limited information on the biology of their local populations. Among this group of non-target species, the piked spurdog - Squalus megalops ) is of special interest because it is a dominant and ecologically important species with high natural abundance. Hence, the main purpose of the present research was to improve knowledge of the basic biology of this species and to provide essential data for its management, sustainable use and conservation. Squalus megalops had a complex population structure, segregating by sex, size and breeding condition. The sex ratio was biased towards females and there was sexual size dimorphism with females attaining a larger maximum size than males. Conversion factors from partial lengths to total length and from partial masses to total mass were determined due to the common commercial fishing practice of eviscerating, beheading and finning sharks. Comparisons of total and partial length - length and mass - length relationships between males and females using different ranges of size showed that there was no effect of size range on measurements reflecting only somatic growth ( fork and carcass lengths ; carcass, pectoral fin and caudal fin masses ). However, for variables reflecting somatic and reproductive growth ( total and liver masses ), different outcomes can be expected when different ranges of size are compared. Examination of dietary composition revealed that S. megalops is an opportunistic predator that consumes a wide range of prey items. High variability was found when overall importance of prey items was estimated. Dietary composition varied in space and time, exhibiting differences among regions, seasons and size classes. Therefore, the intrinsic natural variability in the dietary composition of S. megalops and its spatial and temporal variation in diet suggest that information on the ecological relationships among species is likely to be missed when predator - prey interactions are only inferred from overall diet. Reproductive parameters were determined for population assessment. For both sexes, length - at - maturity differed depending on the criterion adopted for defining maturity. Mature males are capable of mating throughout the year. Females have a continuous asynchronous reproductive cycle. The sex ratio of embryos is 1 : 1 and litter size and nearterm embryo size increase with maternal length. Females have an ovarian cycle and gestation period of two years. Although all females are mature at 600 mm, only 50 % of them are in maternal condition, contributing to annual recruitment each year. Hence, for chondrichthyan species with reproductive cycles of two, three or more years, if maturity ogives are used in population assessments instead of maternity ogives, the models will over - estimate recruitment rates. Age and growth information was also determined for population assessment. Precision estimates, the relationship between spine total length and body length, edge analysis, and agreement between counts on the inner dentine layer and the enameled surface support the use of the first dorsal fin spine for the age estimation of S. megalops. Based on goodness - of - fit criterion, the best growth model for males and females was a two - phase von Bertalanffy function. However, model selection cannot be based on quality of statistical fit only and results should be interpreted with caution. Regardless of the model used, the growth rate of S. megalops, particularly of females, is very low, even within the range of growth rates reported for shark species. A three - levelled hierarchical risk assessment approach was trialed to evaluate the suitability of the approach for S. megalops. Integration of qualitative, semi - quantitative, and quantitative biological and fishing impact data showed that S. megalops is potentially highly susceptible to the effects of fishing. A qualitative assessment indicated that the only fishing related activities to have moderate or high impact on S. megalops were those associated with ' capture fishing ' of the otter trawl, Danish seine, gillnet and automatic longline methods. A semi - quantitative assessment ranked S. megalops at risk because of its low biological productivity and, possibly, its catch susceptibility from cumulative effects across the separate fishing methods. Finally, a quantitative assessment showed that population growth is slow even under the assumption of density - dependent compensation where the fishing mortality rate equals the natural mortality rate. Therefore, conservation and management for sustainable use of S. megalops will require a close control of fishing mortality due to the low capacity of this species to withstand fishing pressure. / Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2006.

The demersal fishery off the west coast of South Africa experiences decreased catches per unit effort of hake, Merluccius capensis and M. paradoxus, following the onset of strong south easterly winds. Research has demonstrated that, during daylight hours, Cape hakes migrate vertically in the water column in response to strong south easterly winds, decreasing their availability to the bottom trawl. Hydroacoustic, trawl and environmental data were collected off the West Coast during both calm and wind-swept periods in an attempt to understand the forces that initiate this behaviour, its spatial variability and the implications for demersal trawl estimates of abundance. Near-bottom currents appear to be the primary factor influencing the vertical distribution of the demersal fish community, of which hake constitutes a large proportion, during daylight hours. Correlation between wind and near-bottom currents suggest that the poleward component of the currents increase in velocity within eight hours following the onset of south easterly winds. The fish avoid boundary layers where currents change direction and speed dramatically, and seem to concentrate in waters with relatively stable current regimes. This result questions the assumption of CPUE-based assessment models that hake availability to the bottom trawl is constant or varies randomly. The incorporation of acoustic assessment techniques to demersal surveys has potential, but may be most valuable by supplementing swept-area estimates of abundance, since the sampling efficiency of these methods varies within the water column. The incorporation of wind indices and gear performance data to Cape hake assessment models have been identified as useful considerations for the future.

The rapid 1980's development of the salmon farming industry in British Columbia has been called "a poorly defined experiment in a poorly understood coastal environment", and the main impetus behind it described as "the chaotic, bottom-line orientation" not only of the industry itself but also of relevant government policy. The purpose of this thesis is to elaborate on these themes by identifying and delineating the most significant reasoning models underlying government development policy; and to offer an evaluation of the policy's 'rationality'. Throughout the development of the industry, but particularly in the early stages, two major areas of uncertainty have been prevalent. First, detailed government policy towards salmon farming has been far from clear - an inarticulation that is characteristic of the philosophy of laissez faire, which was particularly influential in Canadian government policy in the early 1980's. Secondly, a variety of possible ecological impacts have been suspected from the outset. A heuristic approach, both for the basic method employed in the thesis and for the normative model set up to evaluate government policy, is advanced for addressing these different uncertainties. In order to identify relevant policy, it is hypothesized that systems of ideas expressed formally in 'core' models of neoconservative and neoclassical economics were particularly important policy influences. It is argued that the core concept of neoconservative theory (as defined) is the adaptive efficiency of the autonomous market. The theory's fundamental adaptive ideas - economic information 'discovery' by competitive trial-and-error selection, and consumer 'regulation' via the price system - are to be found in representative federal and provincial economic policy documents from the early 1980's, as well as in the occasional government elucidations of B.C. salmon farming policy (scattered in heterogeneous historical sources). An examination of (inferred) specific decisions relevant to ecological aspects of salmon farming reveals the influence of trial-and-error - deliberate omission of government planning - on early salmon farm siting policy; and the influence of the presumption of consumer 'sovereignty', which was assumed to obviate the need for government ecological regulation. The relevant core concept of neoclassical economics (as defined) is the rational model derived from the conception of homo economicus. The model and its derivations are visible in the same early 1980's economic policy documents, which outline public sector 'restraint' criteria, as well as in salmon farming policy elucidations. It is argued that the maximizing 'solution' prescribed by the model is without operational significance in complex, uncertain situations, where ostensible use of the formal technique may be to legitimate decisions taken on other grounds. The normative model set up to evaluate government policy is drawn from three sources: Friedrich Hayek's rationalization of the adaptive market process, C.S. Holling's prescriptions for "adaptive environmental assessment and management", and Herbert Simon's development of "procedural rationality". These models support the conclusion that acquisition of information by the agency that mediates actions and goals - which, in the case of ecological regulation, must be government - has major value as the basis of more rational decisions. But acquiring conclusive evidence by trial-and-error learning involves risk of serious error, particularly irreversible ecological harm, and it is rational to utilize the inconclusive evidence that is always available for making general predictions, in order to guide search and select lesser risks. Incorporating the important constraint of search costs - particularly significant in the economic recession of the early 1980's - the requirements for rational adaptation become minimal, procedural ones of 'reasonableness': lack of bias towards any class of information relevant to social welfare; lack of denial of uncertainties, and thus of development risks, in the complex and little-known salmon farming environment; and timely response to uncertainties subsequently, adequately resolved by experience. It is suggested that all three requirements were infringed by government policy towards salmon farming development. / Science, Faculty of / Resources, Environment and Sustainability (IRES), Institute for / Graduate

Bibliography: pages 168-180. / This thesis adopts an holistic approach to evaluation of the "seal problem", which encompasses the operational and biological interactions between the South African fur seal and fisheries in the Benguela Ecosystem. The operational interactions are examined using a qualitative assessment, and speculative, single-species simulation models are developed to improve understanding of seal population dynamics, present options for seal management and explore seal-fishery interactions. The models show that the probability of a seal living longer than 20 years is 14%; that the population has increased at a rate of 5.1 % p.a. since the last major census in 1983; that in 1988 there were an estimated 1.5 million seals that consumed over 2 million tons of fish; that although seal population size is usually estimated by multiplying the number of pups by a factor of 4, this factor is very variable and under different culling regimes is usually greater than 4; that historically, the mean population : pup ratio is 4.55. The most effective means of reducing the population is to cull both pups and bulls (the population decrease resulting mainly from reduced pup production caused by disturbance during bull culling). Culling pups is the least effective means of population control. Culling cows alters the population sex ratio drastically and is considered undesirable. To achieve a small or negative population growth rate, more bulls and pups need to be culled than have been taken historically. Each of the fisheries is found to be subject to operational interactions with seals, this being most severe for the purse-seine fishery. The per capita consumption of fish by seals is similar under any management regime so it is not justified to adopt a particular culling strategy to reduce overall consumption. When either seal predation or fishing mortality is reduced, the model simulates an increase in fishery yield of Cape hakes. But there is inadequate understanding of hake population dynamics at present, and depending on the interactions between species, decreased predation may result in increased or decreased fishery yields. This study shows that operational interactions are a real problem and this biases the opinion of fishermen towards seals as competitors for fish resources.

Two species of sea turtle, loggerheads (Caretta caretta) and leatherbacks (Dermochelys coriacea) are caught frequently as bycatch in longline fisheries. These fisheries use hooks baited with fish or squid. Yet, leatherbacks feed on gelatinous prey while loggerheads are carnivores. I investigated the responses of these two species to bait odors in controlled laboratory experiments to better understand their feeding behavior and why they interact with longlines. Both species initiated feeding behavior in the presence of squid bait odors and just C. caretta showed feeding behavior with sardine odors; neither responded to mackerel odors. The turtles are hooked differently on longlines. Loggerheads are usually hooked in the mouth while leatherbacks are usually hooked in the shoulder or flippers. Comparisons of prey attack behavior and accuracy in apprehending a stimulus in the presence of waterborne food odors identified speciesspecific differences that may predispose the turtles to particular kinds of hooking. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection