Research Doctorate - Doctor of Philosophy (PhD) / Shrimp farming and capture fishery are two of the major industries of Can Gio district, Ho Chi Minh City, southern Vietnam. These industries have recently developed and contributed to the improvement of local economy. However, they have also raised environmental concerns regarding water pollution and fish stock depletion. The negative impacts of shrimp farm effluents on the water quality of mainstream rivers and fish communities have not been studied in Can Gio. Additionally, there is a lack of research on the influence of the current fisheries management on environmental protection and fish conservation in this district. The goal of this study was to address key issues in fisheries management in Can Gio in regard to the impacts of wastewater from shrimp farming on the water quality of mainstream rivers that affect the local fish communities, and the influence of improper fishing practices that lead to the depletion of local fish stocks. This study also aimed to propose strategies to improve the local fisheries management for more environmentally responsible productions. Two mainstream surveys were developed to obtain data, i.e. environmental surveys for the assessment of water quality and pollution impacts on fish communities; and people interviews for the examination of fisheries management related to shrimp farming and fishing practices. The findings were used as a baseline to develop appropriate strategies for improving the management in terms of promoting sustainable productions both in shrimp farming and capture fishery industries and protecting the environment. This study found that shrimp farming, especially intensive farms have contributed to water pollution in mainstream rivers in Can Gio, and in turn the water pollution has adversely affected the local fish communities. The waters adjacent to the intensive farms were contaminated with high concentrations of organic matter. The number of fish species reduced and tolerant species appeared at higher proportions in these areas. Many improper practices in shrimp farming and fishing as well as weaknesses in government management were addressed to be the key issues leading to environmental pollution and fish depletion. The proposed strategies focused on improving the management at both government and community levels. Promoting community-based management was suggested as a key to the success in fisheries management in Can Gio.

Thesis (M. Sc. (Ichthyology & Fisheries Science))--Rhodes University, 2004.

This dissertation explores why Puerto Rico’s primary stakeholders’ participation in fisheries management is tokenistic at best. While participation discourses are present in Puerto Rico’s fisheries management, a parallel discourse about ‘overfishing’ and the ‘tragedy of the commons’ has created an irreconcilable gap between primary stakeholders and the management institutions. As part of this study I collected data in an arena where various key actors (commercial fishermen, recreational fishermen and agency experts) face each other in the consultation processes, i.e. scoping meetings and public hearings. These encounters proved to occur on an (un)common ground where participation in fisheries policy-making was nearly impossible due to: 1) knowledge conflicts between users and institutional experts/scientists, where each party claimed to possess a more reliable body of knowledge about the marine resource, and 2) a generalised distrust based on different conceptualisations about marine resources and different views of whom, how and why it should (or should not) be managed. I argue that the tensions between the actors involved have led to at least two mechanisms to give the fisheries management apparatus an appearance of stability: 1) the institutionalisation of ignorance and 2) the use of fisheries regulations as a ‘boundary object’ to align the actors, and to fix their identities and responsibilities. In short, participation praxis has been reduced to a minimum given the fissures between scientific knowledge and the primary stakeholders’ knowledge and between marine resource conservation and fishing activity. But above all, participation has been restricted because primary stakeholders distrust institutions that restrict small-scale/artisanal fishing while at the same endorsing construction development in vital coastal habitats. Such development, as understood by the fishermen, is against sound environmental management, given that it impacts negatively on essential ecosystems that are crucial to the fisheries well-being.The majority of the ethnographic research was done in a fishing community in Fajardo, Puerto Rico, over an eleven-month period. I collected qualitative data about commercial fishermen’s views on the marine resource and its management. I also documented how these fishermen negotiated ‘space to manoeuvre’ in the non-participatory environmental management scenario outlined above. The ‘greening’ of commercial fishermen’s discourses is a formidable example.Three months of ethnographic research were also conducted on nearby Culebra Island in an attempt to understand the Marine Protected Area (MPA) of El Canal Luis Peña (CLP) that is ‘marketed’ as a community-based natural reserve and a no-take zone. Although the MPA does not necessarily fulfil all the requirements to be considered a community-based environmental management programme, its creation was definitely a breakthrough in marine resource management participation processes when compared to the main island. Culebra’s MPA is an interesting and challenging case-study that not only contributes to the understanding of how environmental management and policy-making is done and transformed, but also contributes to the question of how, if at all, to put together the pieces when informants disagree.

Blueline Tilefish is a deepwater species that is found along the United States Atlantic coast and in the Gulf of Mexico. Fisheries for the species have developed in the past five decades, and large increases in landings from the mid-2000s to 2010s have raised management interest. During the most recent stock assessment, age reading difficulties found in the past persisted, and preferred age-structured models were not used. Additionally, maturity was estimated from a meta-analysis of other species with similar life histories. Research recommendations from independent peer reviewers thus included improving age determination as well as collection of small fish. We collaborated with charter fishermen to target small (< 400 mm total length [TL]) blueline tilefish. We also collaborated with scientists at South Carolina Department of Natural Resources (SCNDR) on histological reproductive phase coding and ageing of Blueline Tilefish otoliths. We optimized the information incorporated into sex ratio, reproduction, and growth analyses by merging datasets with SCDNR and Old Dominion University (ODU), and assessed first maturity to the increase immature sample size. Overall sex ratios exhibited a female bias, displaying statistically significant deviations from the expected 1:1 ratio in both the Southeast United States Atlantic (SEUS) and United States Mid-Atlantic (USMA) regions. All immature individuals collected measured below 400 mm. Our findings aligned with previously documented spawning seasons, which extend from April to October in the SEUS and from May to November in the USMA, and may extend to November in the SEUS. The spawning peak identified for the SEUS concurred with previous studies, and suggested October as a spawning peak in the USMA—later than previously described. Sex-specific gonadosomatic index analyses indicated no significant differences between regions. Age determination remained challenging, but the level of agreement in age estimates between the VT consensus and SCDNR readings resembled the highest value from previous studies. Evaluation based on AIC and BIC scores of weight-length relationships indicated potential regional differences and sexual dimorphism within both the SEUS and USMA regions. This sexual dimorphism was further supported by von Bertalanffy growth estimates, revealing L_∞ values of 574.7 and 630.1 mm TL and values of 0.22 and 0.24 for females and males, respectively. Analysis of AIC and BIC indicated sexual dimorphic growth. Length and age at 50% maturity estimates ranged from 283 to 357 mm TL and a few months to 3.7 years, respectively. Length at maturity models also indicated that most fish are mature around 400 to 500 mm, highlighting the importance of targeting smaller individuals to increase the sample size of immature fish. Differences in AIC and BIC scores for length and age at maturity models of three maturity scenarios were low (AIC and BIC < 2). We recommend continued investigation into blueline tilefish age determination, as well as targeted efforts to collect more immature blueline tilefish. Additionally, we propose the use of first maturity and data weighting for maturity estimation of this species. / Master of Science / Blueline tilefish, a deepwater species found in the US Atlantic and Gulf of Mexico, has become an increasing concern for fisheries managers due to rising catches in the mid-2000s to early 2010s. In our study, we aimed to better understand this species to support sustainable management as there are uncertainties in some biological characteristics, like early growth and maturity. To this end, we teamed up with charter fishermen and scientists at South Carolina Department of Natural Resources and Old Dominion University to collect small blueline tilefish and learn more about their reproduction and growth. We discovered that the species' sex ratios favor females, deviating significantly from the expected 1:1 ratio in both the Southeast United States Atlantic (SEUS) and United States Mid-Atlantic (USMA) regions. Our research agreed with spawning seasons found in previous studies, which occur from April to October in the SEUS and from May to November in the USMA. It also may suggest that SEUS Blueline Tilefish still spawn in November. We also delved into age determination, a challenging aspect of fisheries science. While it remains a complex task, our agreement rates in age estimates were similar to the highest documented values. Our studies also suggested potential regional differences and sex differences in blueline tilefish growth. Additionally, we estimated that blueline tilefish mature at around 283 to 357 mm in total length and a few months to 3.6 years. We recommend further research into age determination and the collection of more young, small blueline tilefish. Overall, our studies shed light on the unique characteristics of blueline tilefish and highlights the need for continued research to better manage this species.

Sharks and manta rays are being heavily fished in Indonesia due to Asian demand for shark fins and manta gill rakers. The Indonesian government passed legislation in February 2014 to protect the two species of manta rays. A number of shark species have also been protected or banned from export. A major factor in this decision was the proven economic benefits from ecotourism compared to the economic benefits from the shark finning and manta gill industry.However, previous research on marine conservation underlines that there is a lack of social scientific studies on the socio-economic impacts that marine conservation have on stakeholder fishing communities. In an attempt to start filling this gap of knowledge, the purpose of this thesis was to investigate how the shark and manta ray conservation efforts affect the socio-economic situation of different stakeholder fishing communities in Indonesia. Fieldwork was done in fishing communities in the Komodo and Nusa Penida regions, together with the fishing village Tanjung Luar in Lombok, where people in fishing communities were interviewed about their livelihood situation. The study found that the impacts of marine conservation on the economic situation for stakeholder fishermen affects their attitude towards and compliance with marine conservation efforts. If no profitable economic alternatives are given to fishing, fishing communities have a lower degree of compliance with conservation efforts.

This thesis, submitted for the Doctor of Philosophy in Geography and Environment, presents a case study of the development of the UK's market-based management system for oceanic fisheries. Implemented gradually in the years since 1984, the informal nature of the UK's fisheries management system, which has developed through a number of incremental changes and government-industry "gentlemen’s agreements" rather than clear legislative moves, means that few official policy documents (and perhaps consequently, little academic literature) on the subject currently exist. This thesis traces the material and political processes of market formation, looking at the origin of market-based policies in the theories of bioeconomics and wider economic history. It asks what the implicit assumptions of the economic discipline can – and can't – tell us about the impacts and outcomes of market creation, and using a Foucauldian inspired approach to economic performativity, discusses the role of ostensibly descriptive theories in shaping the world around them. Finally, it calls for a greater geographical engagement with marine issues, and proposes an action-research role for geographers in the politics of the sea.

Orientador: Miguel Petrere Junior / Banca: Alpina Begossi / Banca: Serguei Aily Franco de Camargo / Resumo: As bacias do Orinoco e do Amazonas são similares, no sentido de que os dois rios correm em paralelo, em direção ao Oceano Atlântico, têm origem geológica similar e ictiofauna que se sobrepõem quanto ás espécies. O manejo, os impactos socioculturais e o ordenamento jurídico pesqueiro historicamente adotados para se realizar uma pesca responsável, foram revisados nesta dissertação para a Orinoquia venezuelana e Amazônia brasileira. Embora haja diferentes tipos ou estratégias de manejo de recursos naturais e de manejo da pesca em particular tais como: estratégias de manejo convencionais ou tradicionais, de manejo participativo ou comanejo, abordagem de conhecimento ecológico local, manejo adaptativo e mais recentemente o manejo com enfoque ecossistêmico, nesta dissertação foi feita uma análise comparativa para as duas bacias e examinada sua eficiência. Para este propósito se realizou o levantamento de dados secundários e séries históricas de desembarques, composição da frota pesqueira, principais espécies de peixes comerciais, cadeia de comercialização, aspectos técnico-pesqueiros e socioeconômicos dos pescadores das bacias de estudo. Foi realizada uma extensa revisão bibliográfica das características relevantes da Orinoquia venezuelana e da Amazônia brasileira, bem como seus aspectos biogeoquímicos e ecológicos. / Abstract: The Orinoco and Amazonas river basins are similar, in the sense that the two rivers run in parallel, in direction to the Atlantic Ocean, they have similar geological origin and an overlapping fishfauna concerning their species. The socio-cultural impacts and the juridical basis for the management historically adopted for a responsible fishing were revised in this dissertation for the Venezuelan Orinoquia and the Brazilian Amazon. Although there are different types of natural resources management strategies and fisheries in particular as: conventional or traditional management strategies, participative or co-management, approach of local ecological knowledge, adaptive management and more recently the ecosystem approach. So in this dissertation a comparative analysis for the two basins was carried out and its efficiency was examined. For this purpose secondary data and historical series of landings, fishing fleet composition, main commercial fish species, commercialization chain, fisher's socio-economic and technical aspects were examined. An extensive bibliographical revision of the important characteristics of Venezuelan Orinoquia accomplished and of the Brazilian Amazon was accomplished, as well as its biogeochemical and ecological aspects. / Mestre

Connectivity is a major contributor to the overall dynamics of marine populations. However, it still remains challenging to describe connectivity on ecologically meaningful scales of time and space. This is a major impediment to evaluating the impacts of marine protected area with respect to fisheries management objectives. This dissertation brings together a wide array of spatial and connectivity information in the Gulf of Mexico (GOM) with the goal of 1) understanding the spatial distribution of fish populations and source-sink dynamics and 2) evaluating whether this information can be integrated, through a modeling framework, to identify closed areas that could be beneficial to fisheries management in the Gulf of Mexico. First, a generalized additive modelling (GAM) approach is used to describe the distribution of a large number of species groups (i.e. functional groups) across the Gulf of Mexico (GOM) using a large fisheries independent data set (SEAMAP) and climate scale (decades) oceanographic conditions. Next a numerical Lagrangian particle transport model was developed that incorporates two major connectivity processes; site specific larval production and oceanographic transport for an entire large marine ecosystem and over multiple years. The two components are then combined to develop larval dispersal patterns for the entire GOM and identify areas operating as larval sources and sinks. Last, this information is integrated into an end-to-end ecosystem model to evaluate effectiveness of closing source and sink areas for the management of reef fish fisheries. Closed area managemeny simlautions for reef fish indicated closing reef fish source areas, as opposed to sinks, in the GOM is most efficient method of increasing total biomass and yield. However, the impacts across individual functional groups were site specific. Ultimately, these simulations demonstrate the inclusion of connectivity information could improve fishery management objectives in an ecosystem context.

This project investigated the genetic composition of natural populations of Anadara trapezia in Australia at three spatial scales : i) microgeographic (within an estuary, 50 metres to ~ 6 kilometres); ii) microgeographic (within populations, less than 50 metres); and, iii) macrogeographic (hundreds of kilometres along the coast of Australia). Allozyme polymorphism surveys using cellulose acetate strips have revealed, from 43 enzymes screened, 18 putative polymorphic loci. Comparisons of levels of heterozygosity among enzyme structural groups showed no significant differences, however, monomers were significantly more variable as a group than multimers. Significant differences in the level and distribution of polymorphism among functional groups of enzymes were observed. It appears that selection may be acting at the molecular level, not only on a particular locus, but on a group of functionally similar loci. At the macrogeographic scale, significant departures from random mating were observed in most populations. Significant differences in allele distribution among populations of A. trapezia along the east coast of Australia were found. At the macrogeographic scale, heterogeneity of allele frequencies may depend upon the distance separating the populations and surface water currents. Differentiation among population groups in this study is attributed to changes in the direction of the East Australian Current combined with onshore countercurrents. The systematic status of the disjunct western Australian population of A. trapezia was also evaluated as compared with the east coast populations. No evidence of genetic, hence evolutionary divergence was found. The results have serious implications in the management of fisheries as erroneous assumptions in fisheries management models may lead to depletion and near extinction of marine species. The research stresses the necessity of sampling at multiple scales and replication strategies. It also highlighted the complexities researchers are faced with in studies of marine bivalves, such as the presence of null alleles, deficiencies of heterozygotes, apparent inbreeding and the small geographic scales governing population structure. / Doctor of Philosophy (PhD)

An approach to understanding and managing anadromous salmon, steelhead, and sea-run cutthroat trout (Oncorhynchus spp.) based on life history and evolutionary adaptive capacities of species and stocks is presented. Species, stocks, and local populations are viewed as systems that are continuously adapting to changing environmental conditions. They have the potential capacity to evolve in different ways in different environments through both life history and evolutionary adaptation. Habitat organization forms a template for genus, species, stock, and local population life history organization. Harvesting, habitat alteration resulting from land use practices and other human activities can alter the organization and adaptive capacities of species and stocks, and thus their long term persistence. The adaptive capacity of Oncorhynchus relative to its habitat and management environment is examined at the species, stock, and local population levels. Life history characteristics of representative stocks and local populations are analyzed using Detrended Correspondence Analysis (DECORANA). Fresh water migration distance and latitude are used to "explain" ordination patterns of Oncorhynchus species in the North Pacific Basin. Fresh water migration difficulty and mean annual runoff are used to interpret life history patterns of Columbia Basin chinook salmon stocks. Upstream migration difficulty and fall water temperatures are used to explain the ordination patterns of local populations of Willamette spring chinook salmon. Fishery management practices are examined in terms of their impacts on the organization and adaptive capacity of species, stocks, and local populations of Oncorhynchus. Management generalizations and guidelines derived from the life history theory are applied to management of Willamette spring chinook salmon. Maintaining habitat changes in the Willamette Basin within the historic range of fluctuations will tend to maximize co-organization of local populations. Management activities should provide relatively constant habitat and fishery conditions for natural selection processes to "organize" life history traits over a period of at least a few generations. Fisheries should selectively harvest local populations that show a high degree of realization of their adaptive capacity. By focusing instead on maximizing the co-organization of stocks, their habitat and fishery environments, and protecting the adaptive capacities of stocks, we will go a long way toward providing long-term sustainability for social communities dependent on fisheries. / Graduation date: 1994