Made available in DSpace on 2014-12-17T14:33:10Z (GMT). No. of bitstreams: 1 MarcioLFR_DISSERT.pdf: 949735 bytes, checksum: 7b0d7914f06ce721cd7df5864b67525c (MD5) Previous issue date: 2014-02-11 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / When scientists study methods, theory and standards in an inseparable form, he is facing a paradigm. Throughout the development of a determined science, paradigms can change by changing the methods, objective and standards of research. Fisheries science is changing the paradigm moving from the paradigm of maximization in the use of resources, quantified by the index of the catch, which was influenced by evolutionary concepts such as Optimal Foraging Theory, to the sustainability paradigm that seeks its foundation in the fishery ecosystem perspective. The goal of this study was to review methods, theory and the history of ecosystem indexes of fishery science that attempts to determine sustainability of fishery resources from the data capture. Ecosystems indexes by themselves may not be useful to measure the sustainability of fishing because they focus only on the environmental or ecological side of the sustainability tripod. Probably to measure the sustainability of fishing these indexes should include in the future the Payments for Ecosystem Services and Social Resilience. Thus the methods and theories are in constantly changing within science to meet the most current paradigm / Quando o cientista enxerga de forma insepar?vel os m?todos, a teoria e as normas ele est? diante de um paradigma. Ao longo do tempo o desenvolvimento de uma determinada ci?ncia o paradigma pode mudar alterando os m?todos, os objetivos e as normas da pesquisa com o passar dos anos. Ci?ncia Pesqueira transitou de paradigma da maximiza??o na utiliza??o dos recursos, quantificada pelo ?ndice da captura, que foi influenciado por conceitos evolutivos como a Teoria do Forrageamento ?timo para um paradigma da sustentabilidade que busca seu alicerce na perspectiva ecossist?mica da pesca. O objetivo desse trabalho foi realizar uma revis?o que aborda m?todos, teoria e o hist?rico dos ?ndices ecossist?micos da ci?ncia pesqueira que tentam determinar a sustentabilidade dos recursos pesqueiros a partir dos dados de captura. Os ?ndices ecossist?micos talvez n?o consiga mensurar a sustentabilidade da pesca por si s?, porque eles abordam apenas o lado ambiental ou ecol?gico do trip? da sustentabilidade. Provavelmente para se mensurar a sustentabilidade da pesca esses ?ndices devem se juntar no futuro com os Pagamentos por Servi?os Ecossist?micos e a Resili?ncia Social. Assim os m?todos e as teorias se agregam e se reformulam constantemente dentro dessa ci?ncia para atender o paradigma mais atual

Chrysoblephus puniceus is an over-exploited linefish species, endemic to the coastlines off southern Mozambique and eastern South Africa. Over-exploitation and habitat loss are two of the biggest threats to the sustainability of fisheries globally. Assessing the genetic stock structure (a prerequisite for effective management) and predicting climate related range changes will provide a better understanding of these threats to C. puniceus which can be used to improve the sustainability of the fishery. Two hundred and eighty four genetic samples were collected from eight sampling sites between Ponta da Barra in Mozambique and Coffee Bay in South Africa. The mitochondrial control region and ten microsatellite loci were amplified to analyse the stock structure of C. puniceus. The majority of microsatellite and mtDNA pairwise population comparisons were not significant (P > 0.05) although Xai Xai and Inhaca populations had some significant population comparisons for mtDNA (P < 0.05). AMOVA did not explain any significant variation at the between groups hierarchical level for any pre-defined groupings except for a mtDNA grouping which separated out Xai Xai and Inhaca from other sampling sites. SAMOVA, isolation by distance tests, structure analysis, principle component analysis and spatial autocorrelation analysis all indicated a single population of C. puniceus as being most likely. The migrate-n analysis provided evidence of current driven larval transport, with net migration rates influenced by current dynamics.Two hundred and thirty six unique presence points of C. puniceus were correlated with seasonal maximum and minimum temperature data and bathymetry to model the current distribution and predict future distribution changes of the species up until 2030. Eight individual species distribution models were developed and combined into a mean ensemble model using the Biomod2 package. Winter minimum temperature was the most important variable in determining models outputs. Overall the ensemble model was accurate with a true skills statistic score of 0.962. Binary transformed mean ensemble models predicted a northern and southern range contraction of C. puniceus' distribution of 15 percent; by 2030. The mean ensemble probability of occurrence models indicated that C. puniceus' abundance is likely to decrease off the southern Mozambique coastline but remain high off KwaZulu-Natal. The results of the genetic analysis support the theory of external recruitment sustaining the KwaZulu Natal fishery for C. puniceus. While the high genetic diversity and connectivity may make C. puniceus more resilient to disturbances, the loss of 15 percent; distribution and 11 percent; genetic diversity by 2030 will increase the species vulnerability. The decrease in abundance of C. puniceus off southern Mozambique together with current widespread exploitation levels could result in the collapse of the fishery. A single transboundary stock of C. puniceus highlights the need for co-management of the species. A combined stock assessment between South Africa and Mozambique and the development of further Marine Protected Areas off southern Mozambique are suggested as management options to minimise the vulnerability of this species.