Ecologists have long questioned why fluctuating populations tend to persist rather than go extinct. Populations that persist indefinitely are regulated by mechanisms that cause demographic density dependence, which works to bound fluctuation above zero. In a series of studies, I have sought to determine the processes and mechanisms that regulate local populations of coral-reef fish. In the Exuma Keys, Bahamas, fairy basslets (Gramma loreto) live in aggregations on the undersides of coral-reef ledges. These aggregations often constitute local populations because movement between aggregations is rare. The largest individuals occupy prime feeding positions near the front of ledges and force smaller individuals remain near the back where they have lower feeding rates. Based on these initial observations, I designed two experimental studies of the demographic consequences of variation in basslet density. In the first study, I manipulated the density of newly-settled fish to explore the effects of high recruitment on population size. Populations with experimentally elevated recruitment converged in density with unmanipulated populations, primarily due to density-dependent mortality. I found no evidence that density dependence was caused by intraspecific competition; rather it appeared to be due to a short-term behavioral response by predators (aggregative and/or type 3 functional response). In a second study, I manipulated the densities of adults among populations with a standard average density of newly-settled fish. Two measures indicated that the intensity of competition increased at higher densities of adults, which likely made small fish more susceptible to predation, thereby causing density-dependent mortality. Long-term observations indicated that basslet populations were regulated at temporal scales exceeding two generations. At Lizard Island on the Great Barrier Reef, I also examined how patterns of recruitment of coral-reef fishes were modified across a range of natural recruit densities in the presence and absence of resident predators. Predators decreased recruitment and increased mortality for all species, but these effects varied considerably among species. The results of each of these studies stress the importance of both competitive and predatory mechanisms in modifying patterns of abundance established at the time of larval settlement, as well as regulating local population size. / Graduation date: 2002

Under the growing demand for marine fish resources, and the apparent and expected impacts of global climate change, there is a need to conduct long-term monitoring (LTM) to ensure effective management of resources and conservation of biodiversity. However LTM programmes often suffer from design deficiencies and fail to achieve their objectives. These deficiencies stem from the fact that insufficient consideration is afforded to the design phase, with programmes selecting methods that are not suitable to address the objectives, or are not cost-efficient, compromising the sustainability of the LTM. To facilitate the establishment of LTM programmes along the southern coast of South Africa, background research needed to be conducted to identify which methods were most appropriate for LTM of reef fish. This study presents a detailed field-based assessment of the suitability and cost-efficiency of monitoring methods for long-term monitoring of reef fish in the Agulhas Ecoregion of South Africa. The approach adopted to identify the method, or suite of methods most suited for LTM, involved (i) the selection of methods considered suitable for LTM, (ii) the individual assessment and optimisation of method performance, and (iii) the comparative assessment of the fish community sampled by the different methods. The most suited method(s) were then identified as those that provide the most comprehensive assessment of the fish community and had the highest cost-efficiency. The research was conducted between January 2008 and 2011 in the Tsitsikamma and Table Mountain National Park (TNP and TMNP, respectively) marine protected areas (MPAs) within the Agulhas Ecoregion. The methods selected included fish traps (FT), controlled angling (CA), underwater visual census (UVC), remote underwater video (RUV), baited RUV (BRUV) and remotely operated vehicles (ROV). The individual assessment and optimisation was conducted with the FT, UVC, RUV and BRUV methods. The assessment of the FT method aimed to identify the optimal soak time, and whether or not the size of the funnel entrance to the trap affected the catch. The results identified that larger funnel entrances caught more fish and soak times of 80 minutes produced the highest catches per unit effort. However the data were highly variable and the method detected few of the species typical of the region. Fish traps were also associated with high levels of mortality of fish post-release. The assessment of UVC strip transect method involved directly comparing the precision of data collected by researchers and volunteers using a novel double-observer technique (paired-transects). The results showed considerable error in both the volunteers and researchers data, however the researchers produced significantly higher precision data, compared to the volunteers. The distinction between researchers and volunteers was not evident in the data for the dominant species of fish. For all observers, the abundance of a species in the sample had a significant influence on its detectability, with locally scarce or rare species poorly detected. UVC was able to sample the majority of species typical of reefs in the region, however it appeared plagued by observer and detectability biases. The assessments of RUV and BRUV were conducted simultaneously which enabled the assessment of the effect of bait on the observed fish community. In addition the optimal deployment time for both methods to maximise species richness and abundance was determined. The results showed that BRUV, and to a lesser degree RUV, were able to effectively survey the reef fish community for the region with a 50 minute and 35 minute deployment time, respectively. Baited remote underwater video was especially good at detecting the invertebrate and generalist carnivores, and cartilaginous species. On the other hand, RUV was more effective at surveying the microinvertebrate carnivores. Remote underwater video was characterised by higher data variability, compared to BRUV, and was ultimately considered a less cost-efficient monitoring method. Comparative methods assessments were conducted during two field experiments with the FT, UVC and BRUV methods in the TMNP MPA, and the FT, CA, UVC, RUV, BRUV and ROV methods compared in the TNP MPA. The objectives of the comparison were to investigate differences in the fish communities observed with the different methods, and to determine the power of the data to detect an annual 10% growth in the fish populations over a period of five years. The results from the method comparison were in turn used to conduct the cost-benefit analysis to determine the efficiency of the different methods at achieving monitoring objectives requiring population data from multiple trophic and functional groups with the community, and from species of fisheries importance. The results indicated that FT, CA and ROV were ineffective at monitoring the reef fish community, although CA appeared to provide valuable data for the dominant fisheries species. Both CA and FT required minimal initial investment however, the variability in the data translated into high annual monitoring costs, as the required sampling effort was great. The ROV required the highest initial investment and was identified as the least cost-efficient method. Underwater visual census was able to adequately survey the bony fish within the community, however it did not detect the cartilaginous species. Underwater visual census required a large initial investment and was not cost-efficient, as a many samples were required to account for the variability in the data. Remote underwater video provided a comprehensive assessment of the reef fish community, however it too was associated with high levels of variability in the data, compared to BRUV, reducing its cost-efficiency. BRUV provided the most comprehensive assessment of the reef fish community and was associated with the highest cost-efficiency to address the community and fisheries species monitoring objectives. During the course of this research stereo-BRUV has gained considerable support as an effective reef fish monitoring method. Although not tested during this research, stereo-BRUV is preferred to BRUV as it provides accurate data on the size of fish. However, the initial investment of stereo-BRUV is over three times that required for the BRUV. Although it is recommended that a baited video technique be used for LTM in the Agulhas Ecoregion, the choice between BRUV and stereo-BRUV will depend on the specific objectives of the programme and the available budget at the implementing agency.

Artificial reefs (ARs) have been deployed on the inner shelf of Paraná State, south Brazil, to recuperate marine biodiversity and as protection against destructive trawling activities. The purpose of this study was to offer a first characterization of the ichthyoplankton community associated with the ARs and the adjacent archipelago of Currais. Two sampling methodologies were used; 1) plankton net attached to an underwater scooter and; 2) light-traps. A hydrodynamic model was used to study dispersal trajectories to and from the study area. Sampling was conducted between 31.07.14 and 04.04.16. A total of 13 families and 11 species were identified, expanding the total species list of the study area with six species and four families; 63% of fish larvae caught on the ARs were of reef associated species; abundance and species richness was higher on the ARs compared to samples taken at a distance from the ARs. First occurrence of the invasive muzzled blenny Omobranchus punctatus was registered. The hydrodynamic model provided insight on dispersal trajectories and connectivity. The results of this study can be used to better define guidelines for sustainable use of the ARs and the Currais archipelago, a Marine National Park since 2013. / Recifes Artificiais (RA) foram implantados na plataforma interna do Paraná, sul do Brasil, para atuar como unidades anti-arrasto e para oferecer habitat e abrigo para a fauna local, na tentativa de recuperar a biodiversidade marinha ameaçada pelo pesca de arrasto. O principal objetivo deste estudo foi oferecer uma primeira caracterização da assembleia ictioplanctônica associada aos RAs e ao arquipélago de Currais. Coletas foram realizadas utilizando duas metodologias; 1) rede de plâncton acoplado a uma \"scooter\" subaquática e; 2) armadilhas de luz. Excursões amostrais foram realizadas entre 31.07.14 e 04.04.16. Um total de 13 famílias e 11 espécies de peixes representadas no ictioplâncton foram identificadas. Foi registrada a primeira ocorrência do blenídeo invasivo Omobranchus punctatus. A abundância de ictioplâncton foi maior em amostras dos RAs comparado às coletas em área-controle; 63% das larvas capturadas nos RAs foram de espécies recifais. Um modelo hidrodinâmico forneceu uma visão sobre as trajetórias de dispersão larval e conectividade ecológica na região. Os resultados deste estudo podem ser usados para melhor definir diretrizes para o uso sustentável dos RAs e do arquipélago de Currais, um Parque Nacional Marinho desde 2013.

Artificial reefs (ARs) have been deployed on the inner shelf of Paraná State, south Brazil, to recuperate marine biodiversity and as protection against destructive trawling activities. The purpose of this study was to offer a first characterization of the ichthyoplankton community associated with the ARs and the adjacent archipelago of Currais. Two sampling methodologies were used; 1) plankton net attached to an underwater scooter and; 2) light-traps. A hydrodynamic model was used to study dispersal trajectories to and from the study area. Sampling was conducted between 31.07.14 and 04.04.16. A total of 13 families and 11 species were identified, expanding the total species list of the study area with six species and four families; 63% of fish larvae caught on the ARs were of reef associated species; abundance and species richness was higher on the ARs compared to samples taken at a distance from the ARs. First occurrence of the invasive muzzled blenny Omobranchus punctatus was registered. The hydrodynamic model provided insight on dispersal trajectories and connectivity. The results of this study can be used to better define guidelines for sustainable use of the ARs and the Currais archipelago, a Marine National Park since 2013. / Recifes Artificiais (RA) foram implantados na plataforma interna do Paraná, sul do Brasil, para atuar como unidades anti-arrasto e para oferecer habitat e abrigo para a fauna local, na tentativa de recuperar a biodiversidade marinha ameaçada pelo pesca de arrasto. O principal objetivo deste estudo foi oferecer uma primeira caracterização da assembleia ictioplanctônica associada aos RAs e ao arquipélago de Currais. Coletas foram realizadas utilizando duas metodologias; 1) rede de plâncton acoplado a uma \"scooter\" subaquática e; 2) armadilhas de luz. Excursões amostrais foram realizadas entre 31.07.14 e 04.04.16. Um total de 13 famílias e 11 espécies de peixes representadas no ictioplâncton foram identificadas. Foi registrada a primeira ocorrência do blenídeo invasivo Omobranchus punctatus. A abundância de ictioplâncton foi maior em amostras dos RAs comparado às coletas em área-controle; 63% das larvas capturadas nos RAs foram de espécies recifais. Um modelo hidrodinâmico forneceu uma visão sobre as trajetórias de dispersão larval e conectividade ecológica na região. Os resultados deste estudo podem ser usados para melhor definir diretrizes para o uso sustentável dos RAs e do arquipélago de Currais, um Parque Nacional Marinho desde 2013.

Made available in DSpace on 2015-04-17T14:55:24Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1822472 bytes, checksum: 029afda8692ebb7aa8994936007707fb (MD5) Previous issue date: 2012-07-27 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / This study focused on the habitat use and foraging activity of juveniles and adults of the parrotfishes S. axillare and S. frondosum (Perciformes: Scarinae) at the Maracajaú Reefs, state of Rio Grande do Norte. The abundance of two species, habitat characteristics, and food availability were recorded along 60 transects (30 m X 2 m). Foraging activity was characterized by 409 direct observations, using "Animal-focal" and "All occurrences" methodologies. Aggregation and agonistic behaviors associated with foraging activity were also recorded. Canonical Correspondence Analysis (CCA) revealed differences in the spatial distribution of S. axillare and S. frondosum, and between different life phases. Juvenile parrotfishes exhibited the highest feeding rate (bites/minute) while adult S. frondosum terminal phase individuals showed the lowest number of bites. Juvenile and adult parrotfishes ate more frequently Mixed substrate and Sand, items containing large amounts of sediments and detritus in their composition. Feeding selectivity differed between S. axillare and S. frondosum, as well as in relation to life phases and food availability. Only 23% (n=95) of the individuals were sighted foraging in aggregations, mostly adult S. frondosum which formed large mixed schools, mainly with Scarus trispinosus and Acanthurus chirurgus. Attacks of Stegastes fuscus against parrotfishes constituted 76% of the agonistic behaviors recorded. / Este estudo teve como foco o uso do habitat e a atividade de forrageio de jovens e adultos dos budiões Sparisoma axillare e Sparisoma frondosum (Perciformes: Scarinae) nos recifes de Maracajaú, litoral do Rio Grande do Norte. A abundância das duas espécies, as características do habitat e a disponibilidade de itens alimentares foram registradas ao longo de 60 transecções em faixas (30 m X 2 m). A atividade de forrageio foi caracterizada através de 409 observações diretas, utilizando-se os métodos Animalfocal e Todas as ocorrências . Comportamentos de agregação e agonísticos realizados durante a atividade de forrageio também foram registrados. Através da Análise de Correspondência Canônica (CCA) observou-se uma distribuição espacial diferenciada entre S. axillare e S. frondosum, bem como entre suas fases de vida. Jovens de Sparisoma apresentaram a maior taxa de alimentação (mordidas/minuto), enquanto adultos de S. frondosum em fase terminal efetuaram o menor número de mordidas. Durante a alimentação, jovens e adultos de Sparisoma ingeriram com maior frequência os itens Substrato misto e Areia, caracterizados por conter grande quantidade de sedimento e detritos em sua composição. Ambas as espécies apresentaram seletividade ao alimentar-se; esta diferiu entre espécies, fases de vida e disponibilidade de alimento no ambiente. Apenas 23% (n =95) dos indivíduos foram avistados forrageando em agregações, sendo a maioria deles adultos de S. frondosum, que formavam grandes cardumes mistos, principalmente com Acanthurus chirurgus e Scarus trispinosus. Ataques de Stegastes fuscus contra Sparisoma constituíram 76% dos comportamentos agonísticos registrados.

Submitted by João Henrique Costa (henrique@biblioteca.ufpb.br) on 2016-12-19T15:23:59Z No. of bitstreams: 1 Arquivototal.pdf: 1575134 bytes, checksum: 5cce9d619129c20b33fcb9b4d7bcb89b (MD5) / Made available in DSpace on 2016-12-19T15:23:59Z (GMT). No. of bitstreams: 1 Arquivototal.pdf: 1575134 bytes, checksum: 5cce9d619129c20b33fcb9b4d7bcb89b (MD5) Previous issue date: 2016-02-22 / The species Anisotremus moricandi is distributed along the coast of Northeast Brazil and occurs in reef environments near the coast, suffering some human impacts from recreational activities, fishing and pollution. Currently, according to the IUCN (2015), the species is listed in the category “Least Concern” (LC), but despite this position, knowledge about its biology, ecology and fishing is still incipient, which creates great concern about the conservation status of this species. In this sense, this study aimed to characterize the populations and the habitat of A. moricandi on coastal reefs of Cabo Branco e Seixas, which are located in João Pessoa, Paraíba. Samples were collected during the summer period of 2014 and 2015. The abundance and habitat of this species were assessed through daytime snorkeling dives by using linear transects. 60 censuses were conducted (30/site), totaling 227 records of A. moricandi, with a greater number of juvenile individuals, mainly in Cabo Branco reefs. The microhabitat most used by A. moricandi was “reef crevice”, where individuals were seen in most census resting in these structures. The species occur predominantly in areas with rocks. The abundance of A. moricandi was positively related to the amount of reef crevices where juvenile fish use these structures as protection sites. Compared to other studies, it is observed that in Cabo Branco and Seixas reefs there was a greater record of this species, so it can be inferred that these environments have key resources for the survival of A. moricandi. However, it is necessary to preserve these areas in order to maintain that species, as A. moricandi occurs on reefs near shore and is quite vulnerable to human activities. / A espécie Anisotremus moricandi está distribuída da costa do Panamá até o Sudeste do Brasil e ocorre em ambientes recifais próximos à costa, sofrendo alguns impactos antrópicos provenientes de atividades recreativas, pesca e poluição. Atualmente, de acordo com a IUCN (2015), essa espécie é listada na categoria “pouco preocupante” (LC), porém, apesar desse posicionamento, o que se sabe acerca da biologia, ecologia e pesca de A. moricandi ainda é incipiente, o que gera forte preocupação em relação ao estado de conservação dessa espécie. O presente estudo teve como objetivo caracterizar as populações e o habitat de A. moricandi nos recifes costeiros do Cabo Branco e Seixas, que estão situados em João Pessoa, Paraíba. A coleta de dados foi realizada durante o período de verão de 2014 e 2015, onde a abundância e o habitat dessa espécie foram avaliados por meio de mergulhos diurnos livres utilizando-se transectos lineares. Foram realizados 60 censos (30/local), totalizando 227 registros para A. moricandi, havendo um maior número de indivíduos juvenis, principalmente nos recifes do Cabo Branco. O microhabitat mais utilizado por A. moricandi foi “fenda recifal”, onde os indivíduos foram vistos na maioria dos censos em repouso nessas estruturas. A espécie ocorreu predominantemente em áreas com rochas. A abundância de A. moricandi foi positivamente relacionada com a quantidade de fendas recifais, onde os peixes juvenis foram vistos principalmente em repouso, uma vez que essas estruturas fornecem uma maior proteção aos indivíduos. Em comparação a outros estudos, observa-se que nos recifes do Cabo Branco e Seixas houve um maior registro dessa espécie, assim pode-se inferir que esses ambientes possuem recursos primordiais para a sobrevivência de A. moricandi. No entanto, faz-se necessário a preservação dessas áreas visando à manutenção dessa espécie, uma vez que A. moricandi foi registrada em recifes próximos à costa, sendo bastante vulneráveis às ações antrópicas.

Orientadores: Thomas Michael Lewinsohn, Sergio Ricardo Floeter / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-26T00:38:43Z (GMT). No. of bitstreams: 1 Hachich_NayaraFernanda_M.pdf: 4072850 bytes, checksum: 402173284f31340380ff1c754afa1e48 (MD5) Previous issue date: 2014 / Resumo: Os recifes são ecossistemas marinhos fortemente ameaçados. Pressões antrópicas desencadeiam mudanças ambientais e climáticas que interferem direta ou indiretamente na qualidade dos recifes. Estudos sobre ecossistemas marinhos ainda são escassos se comparados à vasta literatura acerca de ecossistemas terrestres. Compreender como a biodiversidade recifal está distribuída e quais os processos que agem sobre a estruturação das comunidades recifais é essencial para a conservação destes ecossistemas. Esta dissertação tem como objetivo investigar os padrões espaciais da distribuição da biodiversidade de organismos recifais no oceano Atlântico. Tais padrões possibilitam inferências acerca dos processos que estruturam as comunidades estudadas. O primeiro capítulo é composto por uma introdução geral da dissertação, que apresenta um referencial teórico e contextual para a compreensão das pesquisas desenvolvidas durante o mestrado. Nessa introdução, apresento brevemente as teorias sobre processos estruturadores de comunidades ecológicas e a contribuição da Biogeografia de Ilhas, Ecologia Funcional e Ecologia Filogenética para o estudo de padrões e processos em comunidades ecológicas. Em seguida, contextualizo a região de estudo, apresentando brevemente a história do oceano Atlântico e o conhecimento dos processos ecológicos e histórico-evolutivos que influenciam a estruturação das comunidades de peixes recifais desse oceano. O segundo capítulo, em forma de artigo científico, trata de padrões de biogeografia de ilhas de peixes recifais, gastrópodes e macroalgas. Neste estudo investiguei como a área de plataforma rasa, isolamento e idade geológica das ilhas oceânicas do Atlântico influenciam a riqueza de espécies e endemismo de organismos recifais que as compõem. Mostrei que os padrões de biogeografia de ilhas de organismos recifais são distintos daqueles encontrados para organismos terrestres e, ainda, que há especificidade taxonômica nos padrões de biogeografia de ilhas entre grupos de organismos recifais. O terceiro capítulo, também em forma de artigo científico, trata de padrões qualitativos da distribuição de duas famílias de peixes recifais (Labridae e Pomacentridae). O objetivo foi compreender a contribuição relativa do ambiente e posição espacial dos recifes na variação da diversidade de peixes recifais entre os recifes do Atlântico ocidental. Neste estudo, investigo como a betadiversidade taxonômica, funcional e filogenética desses organismos varia entre recifes, de acordo com a distância geográfica e a dissimilaridade ambiental entre eles. Os resultados mostraram que a variação na composição de peixes entre recifes do Atlântico ocidental é influenciada principalmente por filtros ambientais e fracamente influenciada por processos que causam autocorrelação espacial na distribuição da biodiversidade. Ainda, as variáveis ambientais que melhor explicaram a diversidade beta de peixes entre os recifes variou fortemente, principalmente entre escalas e regiões biogeográficas, mas também entre famílias de peixes recifais. A dissertação se completa com uma conclusão geral que sintetiza as principais fontes de variação nos padrões de distribuição de organismos recifais no oceano Atlântico (entre escalas, regiões biogeográficas, grupos taxonômicos ou aspectos da biodiversidade) e apresenta um resumo das evidências de processos ecológicos, histórico-evolutivos ou neutros na estruturação das comunidades recifais do oceano Atlântico / Abstract: Reefs are among the most threatened marine systems on earth. Anthropic pressures lead to environmental and climate changes that are able to affect reefs quality, directly or indirectly. Compared to terrestrial ecosystems, marine ones are barely studied. The conservation of reef ecosystems requires the comprehension of reef biodiversity distributional patterns and the processes that modulate them. The aim of this study was to investigate spatial patterns on the distribution of reef biodiversity in the Atlantic Ocean. The study of these patterns allows the inference of processes that structure these communities. The first chapter comprises a general introduction that contextualizes and gives a theoretical framework for the comprehension of the research conducted in this thesis. In this introduction I briefly show the theories concerning processes that structure ecological communities and the potential contribution of Island Biogeography, Functional Ecology and Phylogenetic Ecology to the study of patterns and processes on ecological communities. Then, I contextualize the study region, briefly covering the history of the Atlantic Ocean and the knowledge on the ecological and historical-evolutionary processes that affect the structure of reef fish community in the Atlantic Ocean. In the second chapter, formatted in scientific paper style, I investigate the island biogeographic patterns of reef fish, gastropods and seaweeds. I tested how the shallow shelf area, isolation and geological age of Atlantic oceanic islands influence species¿ richness and endemism of reef organisms. I showed that the patterns observed in reef organisms are different from those observed in the terrestrial ones and, furthermore, that for reef organisms the patterns are taxon-dependent. The third chapter, also formatted in scientific paper style, explore qualitative patterns on the distribution of two families of reef fish (Labridae e Pomacentridae) in the Atlantic Ocean. The aim of this study was to understand the relative contribution of reef environment and spatial location to variation of fish diversity between reefs in the Western Atlantic Ocean. To this end I investigated how the taxonomic, functional and phylogenetic aspects of biodiversity of the two reef fish families vary with spatial distance or environmental dissimilarity between reefs. Results showed that the variation of reef fish composition in Western Atlantic reefs is mainly driven by environmental filters and weakly influenced by processes that cause spatial autocorrelation of species distributions. However, the environmental variables that best explained reef fish beta diversity varied strongly, especially between scales and biogeographical regions, but also between reef fish families. This thesis ends with a general conclusion about the main sources of variation in the patterns of distribution of reef organisms in the Atlantic Ocean (including variation due to scale, biogeographic region, taxonomic group or aspect of biodiversity), as well as with a summary of the evidences of ecological, historical-evolutionary and neutral processes in structuring reef communities in the Atlantic Ocean / Mestrado / Ecologia / Mestra em Ecologia

The fishery is a complex and dynamic socio-ecological system involving several actors and knowledge areas. Along the Brazilian coast the small-scale fisheries are very common and provide important ecosystem services. This fishery modality are usually data-poor in terms of catch and abundance data, landing records, quantification of vessels and fishing gear used. This data-limited condition frequently hampers fishery assessments and effective managements. That is the case in the Abrolhos Bank, East Brazil, a wide portion of the shallow continental shelf that encompass a complex benthic habitat with coral reefs, rhodoliths, buracas, mangroves, seaweed banks and with a great biodiversity. Over this area the small-scale fisheries are a traditional activity, extremely diverse in terms of exploitation capacity, fishing gears, target stocks and operating areas. On the Abrolhos Bank, snappers and groupers are very common resources, besides being predators important for the ecosystem equilibrium. However, these stocks are not evaluated or continuously monitored in the fishing landings and any regional fishery management is currently in place. The overall goal of this thesis was to elucidate questions on three snappers (Lutjanus jocu, Lutjanus synagris and Ocyurus chrysurus) and three groupers (Cephalopholis fulva, Epinephelus morio and Mycteroperca bonaci) fishery characteristics, impacts and sustainability in the Abrolhos Bank. The specific objectives were (1) to assess, organize, and analyze these fisheries to find out patterns on stocks occurrence, on fishing fleets and fishing areas, and to propose management units; (2) to examine the abundance trends and the exploitation status of the six stocks through indicators of size, biomass landed, mortality, spawning and yield, and (3) to evaluate the stocks risk to overexploitation and their fishery sustainability considering biological, environmental social and economic aspects. The study was conducted in four coastal communities of the Abrolhos Bank. The data were obtained by interviews with fishers, experts and stakeholders, from fishery landings monitoring databases, by specimens\' measures in landings and from literature. Groups of stocks co-occurring in landings and groups of stocks co-occurring in fishing grounds were discovered. Seven similar fishing areas were determined and suggested as spatial management units. Overfishing and decline in the relative abundance were detected to five stocks. The major causes of overfishing were high fishing mortality, low spawning potential ratio, low mega-spawners and high juveniles in landings. The fishery has led some stocks on alert to overexploitation and the results revealed that coral reefs habitat and ecosystem are also threaten by mining waste and dredging. Furthermore, there is a weak environmental governance in the region and insufficient community participation in the construction of management proposals. The results reveal a concerning situation regarding the stocks exploitation status but provide the key points to be worked on together the fishing communities. This thesis emphasizes the need for urgent elaboration of fishery regulation measures in the region and may contribute in the delineating of management proposals in this complex and threatened fishery system. / A pesca é um sistema sócio ecológico complexo e dinâmico, envolvendo vários atores e áreas de conhecimento. Ao longo da costa brasileira as pescarias de pequena escala são muito comuns e provém importantes serviços ecossistêmicos. Essa modalidade de pesca frequentemente é pobre em dados de captura e abundância, registros de desembarques, quantificação de embarcações e de artes de pesca utilizadas. Essa condição frequentemente dificulta avaliações pesqueiras e o manejo eficaz. Isso ocorre no Banco dos Abrolhos, leste do Brasil, uma ampla porção da plataforma continental rasa que compreende um complexo habitat bentônico com recifes de corais, rodolitos, buracas, mangues, bancos de algas e com grande biodiversidade. Nesta área, a pesca de pequena escala é uma atividade tradicional extremamente diversificada em termos de capacidade de explotação, artes de pesca, estoques alvo e áreas de operação. No Banco dos Abrolhos vermelhos e garoupas são recursos muito comuns, além de predadores importantes para o equilíbrio do ecossistema. No entanto, estes estoques não são avaliados ou monitorados nos desembarques pesqueiros, e nenhuma gestão pesqueira regional está atualmente em vigor. O objetivo geral desta tese foi elucidar questões sobre as características, impactos e sustentabilidade da pesca de três vermelhos (Lutjanus jocu, Lutjanus synagris and Ocyurus chrysurus) e três garoupas (Cephalopholis fulva, Epinephelus morio and Mycteroperca bonaci) no Banco dos Abrolhos. Os objetivos específicos foram (1) avaliar, organizar e analisar essas pescarias para descobrir padrões de ocorrência de estoques, padrões de frotas e áreas de pesca, e propor unidades de manejo; (2) examinar as tendências na abundância e o status de explotação dos seis estoques por meio de indicadores de tamanho, biomassa desembarcada, mortalidade, desova e rendimento; e (3) avaliar o risco de sobreexplotação dos estoques e a sustentabilidade pesqueira considerando aspectos biológicos, ambientais, sociais e econômicos. O estudo foi realizado em quatro comunidades costeiras do Banco dos Abrolhos. Os dados foram obtidos em entrevistas com pescadores e especialistas locais, em bases de dados de monitoramentos pesqueiros, em medições de espécimes em desembarques e na literatura. Grupos de estoques co-ocorrendo em desembarques e grupos de estoques co-ocorrendo em áreas de pesca foram descobertos. Sete áreas de pesca semelhantes foram determinadas e sugeridas como unidades de manejo espaciais. Sobrepesca e declínio na abundância relativa foram detectados em cinco estoques. As principais causas da sobrepesca foram alta mortalidade por pesca, baixo potencial de desova, poucos mega-reprodutores e muitos juvenis nos desembarques. A pesca deixou alguns estoques em alerta de sobreexplotação e os resultados revelaram que o habitat recifal e o ecossistema são ameaçados também por resíduos de mineração e pela dragagem. Além disso, a governança ambiental na região é fraca e a participação comunitária em propostas de gestão é insuficiente. Os resultados revelam uma situação preocupante quanto ao estado de exploração dos estoques, mas fornecem os pontos-chave a serem trabalhados em conjunto com as comunidades pesqueiras. Esta tese enfatiza a necessidade de elaboração urgente de medidas de regulação pesqueira na região e pode contribuir para o delineamento de propostas de manejo neste complexo e ameaçado sistema pesqueiro.

The fishery is a complex and dynamic socio-ecological system involving several actors and knowledge areas. Along the Brazilian coast the small-scale fisheries are very common and provide important ecosystem services. This fishery modality are usually data-poor in terms of catch and abundance data, landing records, quantification of vessels and fishing gear used. This data-limited condition frequently hampers fishery assessments and effective managements. That is the case in the Abrolhos Bank, East Brazil, a wide portion of the shallow continental shelf that encompass a complex benthic habitat with coral reefs, rhodoliths, buracas, mangroves, seaweed banks and with a great biodiversity. Over this area the small-scale fisheries are a traditional activity, extremely diverse in terms of exploitation capacity, fishing gears, target stocks and operating areas. On the Abrolhos Bank, snappers and groupers are very common resources, besides being predators important for the ecosystem equilibrium. However, these stocks are not evaluated or continuously monitored in the fishing landings and any regional fishery management is currently in place. The overall goal of this thesis was to elucidate questions on three snappers (Lutjanus jocu, Lutjanus synagris and Ocyurus chrysurus) and three groupers (Cephalopholis fulva, Epinephelus morio and Mycteroperca bonaci) fishery characteristics, impacts and sustainability in the Abrolhos Bank. The specific objectives were (1) to assess, organize, and analyze these fisheries to find out patterns on stocks occurrence, on fishing fleets and fishing areas, and to propose management units; (2) to examine the abundance trends and the exploitation status of the six stocks through indicators of size, biomass landed, mortality, spawning and yield, and (3) to evaluate the stocks risk to overexploitation and their fishery sustainability considering biological, environmental social and economic aspects. The study was conducted in four coastal communities of the Abrolhos Bank. The data were obtained by interviews with fishers, experts and stakeholders, from fishery landings monitoring databases, by specimens\' measures in landings and from literature. Groups of stocks co-occurring in landings and groups of stocks co-occurring in fishing grounds were discovered. Seven similar fishing areas were determined and suggested as spatial management units. Overfishing and decline in the relative abundance were detected to five stocks. The major causes of overfishing were high fishing mortality, low spawning potential ratio, low mega-spawners and high juveniles in landings. The fishery has led some stocks on alert to overexploitation and the results revealed that coral reefs habitat and ecosystem are also threaten by mining waste and dredging. Furthermore, there is a weak environmental governance in the region and insufficient community participation in the construction of management proposals. The results reveal a concerning situation regarding the stocks exploitation status but provide the key points to be worked on together the fishing communities. This thesis emphasizes the need for urgent elaboration of fishery regulation measures in the region and may contribute in the delineating of management proposals in this complex and threatened fishery system. / A pesca é um sistema sócio ecológico complexo e dinâmico, envolvendo vários atores e áreas de conhecimento. Ao longo da costa brasileira as pescarias de pequena escala são muito comuns e provém importantes serviços ecossistêmicos. Essa modalidade de pesca frequentemente é pobre em dados de captura e abundância, registros de desembarques, quantificação de embarcações e de artes de pesca utilizadas. Essa condição frequentemente dificulta avaliações pesqueiras e o manejo eficaz. Isso ocorre no Banco dos Abrolhos, leste do Brasil, uma ampla porção da plataforma continental rasa que compreende um complexo habitat bentônico com recifes de corais, rodolitos, buracas, mangues, bancos de algas e com grande biodiversidade. Nesta área, a pesca de pequena escala é uma atividade tradicional extremamente diversificada em termos de capacidade de explotação, artes de pesca, estoques alvo e áreas de operação. No Banco dos Abrolhos vermelhos e garoupas são recursos muito comuns, além de predadores importantes para o equilíbrio do ecossistema. No entanto, estes estoques não são avaliados ou monitorados nos desembarques pesqueiros, e nenhuma gestão pesqueira regional está atualmente em vigor. O objetivo geral desta tese foi elucidar questões sobre as características, impactos e sustentabilidade da pesca de três vermelhos (Lutjanus jocu, Lutjanus synagris and Ocyurus chrysurus) e três garoupas (Cephalopholis fulva, Epinephelus morio and Mycteroperca bonaci) no Banco dos Abrolhos. Os objetivos específicos foram (1) avaliar, organizar e analisar essas pescarias para descobrir padrões de ocorrência de estoques, padrões de frotas e áreas de pesca, e propor unidades de manejo; (2) examinar as tendências na abundância e o status de explotação dos seis estoques por meio de indicadores de tamanho, biomassa desembarcada, mortalidade, desova e rendimento; e (3) avaliar o risco de sobreexplotação dos estoques e a sustentabilidade pesqueira considerando aspectos biológicos, ambientais, sociais e econômicos. O estudo foi realizado em quatro comunidades costeiras do Banco dos Abrolhos. Os dados foram obtidos em entrevistas com pescadores e especialistas locais, em bases de dados de monitoramentos pesqueiros, em medições de espécimes em desembarques e na literatura. Grupos de estoques co-ocorrendo em desembarques e grupos de estoques co-ocorrendo em áreas de pesca foram descobertos. Sete áreas de pesca semelhantes foram determinadas e sugeridas como unidades de manejo espaciais. Sobrepesca e declínio na abundância relativa foram detectados em cinco estoques. As principais causas da sobrepesca foram alta mortalidade por pesca, baixo potencial de desova, poucos mega-reprodutores e muitos juvenis nos desembarques. A pesca deixou alguns estoques em alerta de sobreexplotação e os resultados revelaram que o habitat recifal e o ecossistema são ameaçados também por resíduos de mineração e pela dragagem. Além disso, a governança ambiental na região é fraca e a participação comunitária em propostas de gestão é insuficiente. Os resultados revelam uma situação preocupante quanto ao estado de exploração dos estoques, mas fornecem os pontos-chave a serem trabalhados em conjunto com as comunidades pesqueiras. Esta tese enfatiza a necessidade de elaboração urgente de medidas de regulação pesqueira na região e pode contribuir para o delineamento de propostas de manejo neste complexo e ameaçado sistema pesqueiro.

Thesis (Ph. D. (Ichthyology and Fisheries Science))--Rhodes University, 2006.