Taiwan's surrounding waters rich in terrain, and a number of shares of the sea converge along the coastal waters of Taiwan created a rich fishing ground.However, due to excessive fishing efforts to longterm investment , But lack of proper management of fitness , so even though the number of vessels increased, but the overall fishery production continued to decrease. The management of fisheries resources requires the correct results as the scientific basis for resource assessment , before they can properly apply effective management to achieve goals , and resources conservation and use of a balance between fisheries. The correct resource assessment,you need detailed information on the basis of the catch,the most important time, space and other efforts to catch the amount of information is the most common practitioners of business operating statements made . Taiwan's coastal fisheries,as yet mandatory for the industry to report their operating statements provided management measures , so in the past this type of information is achieved through the visits, but the mission is not only the high cost of information , a small number and accuracy is not high also limited to the funding and cooperation from the fishermen often intermittent , resulting in a serious ack of resources and ssessmenta information. Taiwan Caost Guard Administrstion in order to monitor the waters around Taiwan ,the dynamic vessel offshore the coast of Taiwan are build Caost Radar Systems.These systems approach to proactive scanning , within 24 hours for the scan to monitor vessels and left navigation records including the vessel name , time location information of the vessel .These data separated by fishing information , speed of calculation,it is possible to estimate the fishing vessels fishing effort in the future with the sale of the ships coming into port unloading data information on fishing operations as an alternative complementary information on the shortcomings of the report did not work . The purpose of this study , that Caost Radar Systems in the use of bank information obtained , isolated fishing information , conduct analysis and calculation , and the actual data for verification visits to explore the application of Caost Radar Systems on shore along the coastal fisheries management feasibility . The results showed : Caost Radar Systems data from the isolated shore fishing vessels that the correct information to the operating position, and velocity analysis based on fishing operations , can estimate fishing effort,and calculate the frequency of operating out of position, draw fishing boats operating region .But the study also found the sea wave and blind area factor will be off the lock occur ,resulting in boat speed and position information a short time gaps , but this does not affect the overall assessment of fishery resoures, through projections to supplement the information in this section.

Abstract Taiwan is surrounded by the ocean with enriched marine eco-diversity and coastal terrains, making it a land of abundant fishery resources. Yet, after Taiwan was returned to ROC in 1945, the abuse of inshore fishery due to economical development resulted in overfishing. Under the development of industrialization, marine pollution and the use of destructive fishing gear have also caused a great damage to the ecological and biological diversities along the inshore to the drastic decrease in fisheries. Thus, how the government may find a balance between sustainability in fishery resources and economical development in local fishing communities is the major interest of this study. The present research conducts the work through the collection of annual fishing statistics and the questionnaire survey of local fishermen and government administrators. This study analyzes the changing trends of inshore fishery in Taiwan and investigates the effectiveness of current fishery regulations and the policy of fishing transformation along the inshore in Taiwan. The fisheries administration is currently adapting several fishery regulatory measures which include fishery licenses, replacement of boats and fishing vessels, and suspension of fishing activities / fishing moratorium for the management of fishery resources. Yet the fishery resources are still shrinking each year. It is obvious that those measures are ineffective on slowing down the speedy drop of fishery resources. The survey results showed that the effective administrative efforts should involve the regulation policy on fishing gears, fishing methods, fishing zones, and fishing seasons. A top-down fishery management system should be integrated with the bottom-up fishermen¡¦s autonomy, in order to establish a feasible coordination system between fishermen and the administration. In the long term, in addition to the management of some target fishes, it is important to integrate the fishery policy and management with the sustainable management of the living environment and ecosystem. These should include the assigning fishery preservation areas and the protection of the marine habitats to ensure biological diversity and to maintain the sustainable fishery resources. To reduce the fishing impact on fishery resources involving buy out the additional fishing boats, the government should actively help fishermen on their career reform. The government should also encourage the conversion of overcapacity fishing boats to the entertainment fishery. Yet through questionnaires and interviews, this study has found that most fishermen are reluctant to change their career owing to the lack of specialties and the high cost of boat remodeling. This study suggests that marine tourist vessels and whale-watching boats should be categorized as entertainment boats under the jurisdiction of the Ministry of Communication. Yet, small fishing-entertainment boats are mainly for marine fishing, or watching traditional fishing / net caging operations, and tourist diving that all operate during the off-seasons. For this, the government should provide various fishing trainings, improve the harbor facilities for entertainment fishery, and cultivate all citizens¡¦ feelings of love for the ocean to promote the marine tour vacationing and the entertainment fishery. In the coastal 200 nautical miles exclusive fisheries zone, involving fishery habitat and reproduction ground, is the sovereign right control area of every coastal country. Thus, the government is entitled to decide the optimum fishery utilization independently as the basis of the fishery development for the food security, environment and resources conservation, and fishing community social stability. The present work concludes that government should plan and establish strategies for an effective management on the inshore fishery to ensure a sustainable fishery development.

Abstract Taiwan is an island country, the topography of the adjacent territorial waters is diversified, multiple ocean currents converge here and there are rich basic production capabilities, all of which give birth to various marine organisms in Taiwan and help to form the favorable conditions for Taiwan to develop its offshore fishery. However, due to the lack of control of the production capabilities of offshore waters in the last few decades, plus the constant upgrading of fishing techniques and methods, as well as the lack of effective management, the fishery resources have been greatly impacted and the total fishery production continues to decline. Fishery resource management needs correct fishing location, fishing effort and catch totals as the scientific basis for fish stock assessment, in order to achieve effective management targets. The greatest problem for the offshore waters of Taiwan is that we could not obtain detailed information on the fishing location, operation time (fishing effort) and catch totals. At present, the above data were all obtained through investigations or by interviewing with captains to fill in report forms. However, out of fear of disclosing trade secrets and owing to omissions, the obtained data could not help in revealing the real fishery resource situation. The Coast Guard Administration of the Executive Yuan integrally established a coast radar system along the coast of Taiwan, which monitors all ships within the scanning area through 24-hour uninterrupted scanning, and digitally records the navigation data on ships. The data contains time, ship number, speed, course, latitude and longitude (location); by sorting out these data, we could discern the actual fishing location of the fishing boats. The objective of this study was to utilize the data collected by the coast radar system to determine the fishing location of the fishing boats, acquire the port entry and exit data of the fishing boats through the security examination system, work out the fishing effort, and by collecting the catch and sales data from five fishery harbors, derive the respective total amount of the 10 main fish species caught, in order to investigate the fishery dynamics of Southern Taiwan sea. Research results show that by applying the coast radar system along with the use of port entry and exit data on the fishing boats recorded in the security examination system, as well as the catch and sales data of the fishing boats, and through comparison of the above data, we could obtain proper estimations of fishing effort and fishing location of the fishing boats, as well as the catch per unit effort (CPUE) and the distribution of species composition. Keywords: coast radar, Tainan coastal and offshore fisheries, fishing effort, fishing location¡Acatch per unit effort

Submitted by Anaclaudia Mattos Villalba (anaclaudiamattosvillalba@gmail.com) on 2016-04-09T22:49:54Z No. of bitstreams: 1 youblisher.com-1121544-Disserta_o_Paulo_Roberto_Santos_dos_Santos.pdf: 1064090 bytes, checksum: eedf7bfcf7e22c42250917e5321c9714 (MD5) / Approved for entry into archive by cleuza maria medina dos santos (cleuzamai@yahoo.com.br) on 2016-04-21T02:08:25Z (GMT) No. of bitstreams: 1 youblisher.com-1121544-Disserta_o_Paulo_Roberto_Santos_dos_Santos.pdf: 1064090 bytes, checksum: eedf7bfcf7e22c42250917e5321c9714 (MD5) / Made available in DSpace on 2016-04-21T02:08:25Z (GMT). No. of bitstreams: 1 youblisher.com-1121544-Disserta_o_Paulo_Roberto_Santos_dos_Santos.pdf: 1064090 bytes, checksum: eedf7bfcf7e22c42250917e5321c9714 (MD5) Previous issue date: 2015 / O aumento na abundância de peixes não residentes da zona estuarina, atraem o interesse da frota pesqueira, que atua sobre os estoques de forma intensa, muitas vezes levando a sobreexplotação. No estuário da Lagoa dos Patos, a Miragaia (Pogonias cromis), é um peixe estuarino dependente que por muitos anos foi um importante recurso pesqueiro, e hoje encontra-se sobreexplotado e ameaçado de extinção. As capturas que atingiram 1400 t em 1976, decaíram posteriormente e foram inexistentes nos anos de 2004, 2005, 2008, 2009 e 2010. Mas recentemente, se observa o aumento dos desembarques na região. A partir disso, a presente dissertação tem por objetivo descrever a pesca artesanal da Miragaia no estuário da Lagoa dos Patos e analisar o efeito da sobreexplotação no ciclo reprodutivo da população remanescente na região. No primeiro capítulo intitulado "A pesca artesanal da Miragaia (Pogonias cromis, Scieanidae) no estuário da Lagoa dos Patos", é discutida a hipótese de que os maiores valores de esforço e CPUE são encontrados no mesmo período de maior abundância da espécie no estuário, e verifica-se a influência do esforço de pesca nas variações da CPUE. De forma complementar, se confirma a distinta composição dos desembarques entre o período de desova e o resto do ano, a predominância de adultos no período de desova evidencia o aumento da abundância. No segundo capítulo intitulado "O efeito da sobreexplotação no ciclo reprodutivo da Miragaia (Pogonias cromis, Scieanidae)" é discutido a redução da idade e tamanho de primeira maturação sexual e consequentemente fecundidade dos exemplares, como consequência da sobrepesca sofrida pela espécie em anos anteriores. Os resultados encontrados mostram a situação preocupante da população de Miragaias no estuário da Lagoa dos Patos, onde a manutenção da intensidade pesqueira pode levar ao colapso da atividade e posterior extinção local da espécie. / The increase in the abundance of non-resident fish estuarine zone attract the interest of the fishing fleet, which operates on the intensely stocks, often leading to overexploitation. In the estuary of Patos Lagoon, the Black drum (Pogonias cromis) is an estuarine-dependent fish who for many years was an important fishing resource, and today is overexploited and threatened with extinction. Catches reached 1400 t in 1976, declined later and were negligible in the years 2004, 2005, 2008, 2009 and 2010. But recently observed increased landings in the region. Thus, this thesis aims to describe artisanal fishing of Black drum in the estuary of Patos Lagoon and analyze the effect of v overexploitation in the reproductive cycle of the remaining population in the region. In the first chapter entitled "The artisanal fishery Black drum (Pogonias cromis, Scieanidae) in the estuary of Patos Lagoon," discusses the hypothesis that higher values of effort and CPUE are found in the same period of greatest abundance of the species in the estuary, and there is the influence of fishing effort in changes in CPUE in a complementary way confirms the different composition of landings spawning periods for the rest of the year, the prevalence of adults in spawning highlights the increasing abundance. In the second chapter entitled "The effect of overexploitation in the reproductive cycle of Black drum (Pogonias cromis, Scieanidae)" is discussed reducing the age and size at first sexual maturity and consequently fertility of copies as a result of overfishing suffered by the species in previous years. The results show the worrying situation of the population of Black drum in the estuary of Patos Lagoon, where the maintenance of fishing intensity can lead to the collapse of activity and subsequent local extinction of the species.

Les aires marines protégées (AMPs), soulèvent un intérêt croissant pour leur capacité à améliorer la conservation des ressources marines et, potentiellement, les captures des pêcheries au travers de l'export de poissons et de larves vers les zones pêchées. Des lacunes importantes subsistent dans nos connaissances des impacts du mouvement des poissons sur le fonctionnement des AMPs, et sur la manière dont les AMPs protégeant les populations de poissons modérément à fortement mobiles pourraient être efficaces sans être extrêmement larges. Différents modèles sont utilisés ici afin de combler ces lacunes de connaissances. Tout d'abord, un modèle conceptuel a été développé afin d'explorer les impacts du mouvement des poissons sur l'efficacité des AMPs comparativement à ceux de la dispersion larvaire. Les résultats de ce modèle démontrent que le mouvement des poissons a un impact négatif plus fort sur la persistance d'une population dans les réseaux d'AMPs que la dispersion larvaire. La redistribution de l'effort de pêche anciennement dans les AMPs et la concentration des pêcheurs en bordure d'AMPs réduisent de façon significative la persistance et les captures des populations se dispersant dans le stade adulte, tandis qu'elles n'ont qu'un effet marginal pour les populations se dispersant dans le stade larvaire. Deux modèles appliqués ont été ensuite développés afin d'examiner les impacts des AMPs protégeant des fractions spécifiques de populations migratrices. Un modèle spatialement explicite a été utilisé afin d'étudier les effets des AMPs pour deux populations de merlus sud africaines effectuant des migrations ontogéniques. Les résultats de ce modèle montrent que les AMPs ciblant les juvéniles entraînent une augmentation considérable de la biomasse féconde. Cette augmentation de biomasse conduit à une amélioration des captures de certaines, mais pas de toutes les flottes de pêche. Un modèle par recrue est utilisé afin d'évaluer les effets des AMPs pour les populations récifales effectuant des migrations pour former des agrégations de ponte transitoires. L'application de ce modèle à deux populations de poissons des Seychelles révèle que les AMPs protégeant les agrégations de ponte augmentent le potentiel reproductif des poissons en général, mais pas les captures par recrue. / Marine protected areas (MPAs) are increasingly considered for their ability to improve species conservation and, potentially, fisheries yields via the export of fish and larvae to fished areas. Critical knowledge gaps remain on the impacts of fish movement for MPA functioning and on how MPAs protecting moderately to highly mobile populations may be effective without being extremely large. Here, different models are used to address these knowledge gaps. First, a conceptual model was developed to explore the impacts of fish movement versus larval dispersal on MPA effectiveness. Results demonstrate that fish movement has a stronger negative impact on population persistence in MPA networks than larval dispersal. Redistribution of the fishing effort formerly in MPAs and concentration of fishers on MPA borders dramatically reduce persistence and yields for mobile populations, while they marginally change results for populations with dispersing larvae. Two applied models examining the effects of MPAs targeting specific fractions of migratory populations were then developed. A spatially-explicit model was used to study the effects of MPAs on two South African hake populations undergoing ontogenetic migrations. Results show that MPAs targeting juveniles considerably increase hake spawning biomass. This increase in biomass improves the yields of some, but not all fishing fleets. A per-recruit model was used to assess MPA effects for reef populations migrating to form transient spawning aggregations. Applying the model to two populations from Seychelles, MPAs protecting spawning aggregations are found to improve fish reproductive potential in general, but not yield-per-recruit.

Dentro do contexto de crise global pesqueira que afeta tanto a pesca industrial quanto a artesanal, este trabalho visa descrever e analisar a pesca artesanal de emalhe no sul do Brasil, além de estudar a interação entre essa pesca artesanal e as tartarugas marinhas. O capítulo 1 consiste na caracterização social, econômica e operacional da pesca artesanal, avaliando o esforço pesqueiro de suas diferentes modalidades. A análise dos dados fornecidos por pescadores revelou a diferenciação na captura e esforço entre dois grupos de embarcações: barcos até 12,5 metros de comprimento total e barcos acima de 12,5 metros. As entrevistas também geraram uma ilustração que demonstra a sobreposição da área de atuação dos pescadores. Neste capítulo são propostas medidas de gestão da pesca artesanal de emalhe que consideram o rendimento dos pescadores e preservam os recursos pesqueiros. No capítulo 2 foram analisados fatores sociais e operacionais da pesca relacionados à captura incidental de tartarugas marinhas. Entrevistas com pescadores (n=92) e desembarques monitorados pelos pescadores (n=320) registrados em locais de pesca dentro e fora de Unidades de Conservação Marinhas no Rio Grande do Sul e Santa Catarina verificaram a influência do manejo espacial sobre as capturas incidentais. Analisou-se também o conhecimento ecológico local (CEL) dos pescadores sobre as tartarugas marinhas. A criação de zonas exclusivas para a pesca artesanal e o aumento de vistorias às redes de pesca são propostas para reduzir as capturas incidentais pela pesca artesanal de emalhe no sul do Brasil, através do envolvimento dos pescadores nas pesquisas e do co-manejo dos recursos pesqueiros. / Within the context of global fishing crisis that affects both industrial and artisanal fisheries, this survey aims to describe and analyze the artisanal gillnet fishery in southern Brazil and study the interaction between this fishing and sea turtles. The chapter 1 consists in social, economic and operational characterization of artisanal fisheries, assessing the fishing effort of different kinds of fisheries. The analysis of data provided by fishermen revealed the differentiation in catch and effort between two vessel’s groups: boats up to 12.5 meters long and boats over 12.5 meters. The interviews also show the spatial overlap of areas of operation of fishers. In this chapter we proposed measures for the management of small-scale gillnet fishing that consider the income of fishermen and preserve fish stocks. In chapter 2 we analyzed social and operational fishing factors related to bycatch of sea turtles. Interviews (n=92) and landings (n=320) recorded in fishing grounds inside and outside of Marine Protected Areas in Rio Grande do Sul and Santa Catarina assessed the influence of the spatial management on bycatch. It analyzed also the local ecological knowledge (LEK) of fishers about sea turtles. The creation of exclusive zones for artisanal fishing and to increase inspections of fishing nets are presented to reduce incidental catches by artisanal gillnet fishing in southern Brazil, such as the involvement of fishermen in research and co-management of resources.

Los objetivos de la tesis fueron estudiar los factores que pueden explicar la variabilidad existente en la distribución e intensidad de la pesca artesanal en torno a una reserva marina (RM), valorar el efecto de la protección sobre la pesca y analizar y valorar los efectos bio-económicos de configuraciones alternativas de diseño y gestión. Los resultados revelaron que las embarcaciones artesanales calan más artes, de menor longitud, en zonas de elevada diversidad de hábitats. El rendimiento pesquero depende del nivel de protección, la distancia a la RM y la diversidad de artes por unidad de área. La protección está teniendo resultados positivos sobre las poblaciones de peces explotadas y beneficiando a la economía local. El aumento de superficie protegida, distribuido en varias reservas integrales en emplazamientos adecuados, distanciadas unas decenas kilómetros, más que la reducción del esfuerzo, tendría efectos positivos sobre el poblamiento de peces y la economía local. / The aim of the present work is to study the factors that may explain the variability in distribution and intensity of artisanal fishing around a marine reserve, evaluate the reserve effect and analyze and assess the biological and economic effects of alternative configurations of a marine protected area. The results revealed that artisanal vessels used more fishing gears, but shorter, in high habitat diversity areas. The fishing yield depends of protection level, distance to marine reserve and diversity of fishing gears per unit area. The protection measures have had positive results on exploited fish populations and in the local economy. The increase of protected area surface, distributed on several no take zones at appropriate locations, a few kilometers apart, more than the reduction of the fishing effort, would have positive effects on the population of commercial fishes and the local economy.

Dentro do contexto de crise global pesqueira que afeta tanto a pesca industrial quanto a artesanal, este trabalho visa descrever e analisar a pesca artesanal de emalhe no sul do Brasil, além de estudar a interação entre essa pesca artesanal e as tartarugas marinhas. O capítulo 1 consiste na caracterização social, econômica e operacional da pesca artesanal, avaliando o esforço pesqueiro de suas diferentes modalidades. A análise dos dados fornecidos por pescadores revelou a diferenciação na captura e esforço entre dois grupos de embarcações: barcos até 12,5 metros de comprimento total e barcos acima de 12,5 metros. As entrevistas também geraram uma ilustração que demonstra a sobreposição da área de atuação dos pescadores. Neste capítulo são propostas medidas de gestão da pesca artesanal de emalhe que consideram o rendimento dos pescadores e preservam os recursos pesqueiros. No capítulo 2 foram analisados fatores sociais e operacionais da pesca relacionados à captura incidental de tartarugas marinhas. Entrevistas com pescadores (n=92) e desembarques monitorados pelos pescadores (n=320) registrados em locais de pesca dentro e fora de Unidades de Conservação Marinhas no Rio Grande do Sul e Santa Catarina verificaram a influência do manejo espacial sobre as capturas incidentais. Analisou-se também o conhecimento ecológico local (CEL) dos pescadores sobre as tartarugas marinhas. A criação de zonas exclusivas para a pesca artesanal e o aumento de vistorias às redes de pesca são propostas para reduzir as capturas incidentais pela pesca artesanal de emalhe no sul do Brasil, através do envolvimento dos pescadores nas pesquisas e do co-manejo dos recursos pesqueiros. / Within the context of global fishing crisis that affects both industrial and artisanal fisheries, this survey aims to describe and analyze the artisanal gillnet fishery in southern Brazil and study the interaction between this fishing and sea turtles. The chapter 1 consists in social, economic and operational characterization of artisanal fisheries, assessing the fishing effort of different kinds of fisheries. The analysis of data provided by fishermen revealed the differentiation in catch and effort between two vessel’s groups: boats up to 12.5 meters long and boats over 12.5 meters. The interviews also show the spatial overlap of areas of operation of fishers. In this chapter we proposed measures for the management of small-scale gillnet fishing that consider the income of fishermen and preserve fish stocks. In chapter 2 we analyzed social and operational fishing factors related to bycatch of sea turtles. Interviews (n=92) and landings (n=320) recorded in fishing grounds inside and outside of Marine Protected Areas in Rio Grande do Sul and Santa Catarina assessed the influence of the spatial management on bycatch. It analyzed also the local ecological knowledge (LEK) of fishers about sea turtles. The creation of exclusive zones for artisanal fishing and to increase inspections of fishing nets are presented to reduce incidental catches by artisanal gillnet fishing in southern Brazil, such as the involvement of fishermen in research and co-management of resources.

Dentro do contexto de crise global pesqueira que afeta tanto a pesca industrial quanto a artesanal, este trabalho visa descrever e analisar a pesca artesanal de emalhe no sul do Brasil, além de estudar a interação entre essa pesca artesanal e as tartarugas marinhas. O capítulo 1 consiste na caracterização social, econômica e operacional da pesca artesanal, avaliando o esforço pesqueiro de suas diferentes modalidades. A análise dos dados fornecidos por pescadores revelou a diferenciação na captura e esforço entre dois grupos de embarcações: barcos até 12,5 metros de comprimento total e barcos acima de 12,5 metros. As entrevistas também geraram uma ilustração que demonstra a sobreposição da área de atuação dos pescadores. Neste capítulo são propostas medidas de gestão da pesca artesanal de emalhe que consideram o rendimento dos pescadores e preservam os recursos pesqueiros. No capítulo 2 foram analisados fatores sociais e operacionais da pesca relacionados à captura incidental de tartarugas marinhas. Entrevistas com pescadores (n=92) e desembarques monitorados pelos pescadores (n=320) registrados em locais de pesca dentro e fora de Unidades de Conservação Marinhas no Rio Grande do Sul e Santa Catarina verificaram a influência do manejo espacial sobre as capturas incidentais. Analisou-se também o conhecimento ecológico local (CEL) dos pescadores sobre as tartarugas marinhas. A criação de zonas exclusivas para a pesca artesanal e o aumento de vistorias às redes de pesca são propostas para reduzir as capturas incidentais pela pesca artesanal de emalhe no sul do Brasil, através do envolvimento dos pescadores nas pesquisas e do co-manejo dos recursos pesqueiros. / Within the context of global fishing crisis that affects both industrial and artisanal fisheries, this survey aims to describe and analyze the artisanal gillnet fishery in southern Brazil and study the interaction between this fishing and sea turtles. The chapter 1 consists in social, economic and operational characterization of artisanal fisheries, assessing the fishing effort of different kinds of fisheries. The analysis of data provided by fishermen revealed the differentiation in catch and effort between two vessel’s groups: boats up to 12.5 meters long and boats over 12.5 meters. The interviews also show the spatial overlap of areas of operation of fishers. In this chapter we proposed measures for the management of small-scale gillnet fishing that consider the income of fishermen and preserve fish stocks. In chapter 2 we analyzed social and operational fishing factors related to bycatch of sea turtles. Interviews (n=92) and landings (n=320) recorded in fishing grounds inside and outside of Marine Protected Areas in Rio Grande do Sul and Santa Catarina assessed the influence of the spatial management on bycatch. It analyzed also the local ecological knowledge (LEK) of fishers about sea turtles. The creation of exclusive zones for artisanal fishing and to increase inspections of fishing nets are presented to reduce incidental catches by artisanal gillnet fishing in southern Brazil, such as the involvement of fishermen in research and co-management of resources.

Tese(doutorado) - Universidade Federal do Rio Grande, Programa de Pós–Graduação em Oceanografia Biológica, Instituto de Oceanografia, 2011. / Submitted by Cristiane Gomides (cristiane_gomides@hotmail.com) on 2013-12-15T11:04:17Z No. of bitstreams: 1 leonrdo.pdf: 9078429 bytes, checksum: af7d36e3035868040d998b9669ce02ee (MD5) / Approved for entry into archive by Sabrina Andrade (sabrinabeatriz@ibest.com.br) on 2013-12-18T17:39:33Z (GMT) No. of bitstreams: 1 leonrdo.pdf: 9078429 bytes, checksum: af7d36e3035868040d998b9669ce02ee (MD5) / Made available in DSpace on 2013-12-18T17:39:33Z (GMT). No. of bitstreams: 1 leonrdo.pdf: 9078429 bytes, checksum: af7d36e3035868040d998b9669ce02ee (MD5) Previous issue date: 2011 / Utilizando dois bancos de dados mensais (1979-1984; 1996-2011) constituídos por um regime de amostragens experimentais independentes da pesca, o objetivo deste estudo foi avaliar a hipótese central de que mudanças de longo prazo na abundância e diversidade de peixes nas zonas rasas do estuário da Lagoa dos Patos (ZRELP) ocorreram nas últimas 3 décadas, as quais foram promovidas por distúrbios nos habitats estuarinos e alterações no esforço de pesca na região. Os padrões de composição e abundância das espécies de peixe que utilizam as ZRELP apresentam alta variabilidade anual e inter-anual, as quais são reguladas principalmente pelas variações ou flutuações da temperatura, salinidade, vazão estuarina e componente meridional do vento. Os resultados deste estudo revelam que o Modo Anular Sul (SAM) também parece influenciar a dinâmica temporal dos peixes nas ZRELP, além do El Niño Oscilação Sul (ENOS), e que o tempo de resposta das espécies em relação a alguns fatores abióticos (e.g., temperatura e vazão) não é instantâneo. Por fim, o presente estudo revela que mudanças de longo prazo ocorreram na abundância e diversidade das espécies nos últimos 30 anos. Estas mudanças estiveram provavelmente associadas às alterações nas condições hidrológicas do estuário promovidas pelos fenômenos ENOS e SAM. A perda de habitat, especialmente dos vegetados, e a pressão de pesca representada pelo esforço de pesca também parecem ter importante papel sobre as mudanças de longo prazo observadas, principalmente para espécies como a Brevoortia pectinata, Jenynsia multidentata, Micropogonias furnieri e Mugil liza. A partir do conjunto de informações reunidas, o presente estudo reforça a hipótese que os padrões de uso do estuário da Lagoa dos Patos, especialmente pelos juvenis, estão fortemente vulneráveis às mudanças no clima e às transformações antrópicas do estuário, a despeito da alta variabilidade destes padrões forçada pelo dinamismo estuarino. / Using two long-term database (1979-1984; 1996-2011) composed by experimental fishery-independent sampling survey, the aim of this study was to evaluate the main hypothesis that long-term changes in fish abundance and diversity in shallow areas of the Patos Lagoon Estuary (SAPLE) occurred in the last three decades, which were promoted by estuarine habitats disturbances and alterations in fishing effort changes in the region. The composition and abundance patterns of fish species inhabiting SAPLE present high annual and inter-annual variability, which are mainly regulated by changes or fluctuations in temperature, salinity, freshwater outflow into the estuary and meridional wind component. The results show that the Southern Annular Mode (SAM) also seems to be influencing the temporal dynamics of fishes in SAPLE besides of the El Niño Southern Oscillation (ENSO), and that time response of species to changes in some environmental variables (e.g., temperature and freshwater outflow) is not in phase. Finally, this study shows that long-term changes occurred in the species abundance and diversity in the last 30 years. These changes were probably associated to changes in the estuarine hydrological conditions promoted by ENSO and SAM phenomena. The habitat loss, especially of the vegetated ones, and the fishing pressure represented by fishing effort also seem to have important role on observed long-term changes, especially to Brevoortia pectinata, Jenynsia multidentata, Micropogonias furnieri e Mugil liza. From the total information gathered, the present study reinforce the hypotheses that the fish use patterns in the Patos Lagoon estuary, especially by juveniles, are highly vulnerable to climate change and to man-induced estuarine transformations, despite the high variability of these patterns associated with the estuary dynamics.