Submitted by Mendes Eduardo (dasilva@ufba.br) on 2013-08-20T16:53:26Z No. of bitstreams: 1 Dissertação José Amorim Reis-Filho.pdf: 9945243 bytes, checksum: eabc5d59a3ada6a82b6794d36b3ae991 (MD5) / Approved for entry into archive by Alda Lima da Silva(sivalda@ufba.br) on 2013-08-20T21:14:42Z (GMT) No. of bitstreams: 1 Dissertação José Amorim Reis-Filho.pdf: 9945243 bytes, checksum: eabc5d59a3ada6a82b6794d36b3ae991 (MD5) / Made available in DSpace on 2013-08-20T21:14:42Z (GMT). No. of bitstreams: 1 Dissertação José Amorim Reis-Filho.pdf: 9945243 bytes, checksum: eabc5d59a3ada6a82b6794d36b3ae991 (MD5) / Capes / Public awareness regarding environmental issues has increased in recent decades. The increasing number of impact assessment studies, management and conservation plans, as well as ecological monitoring studies, demand new and more efficient techniques. We collected fishes and environmental variables in three zones (upper, middle and lower) of a tropical estuary during ebb tide. The aim was to test for differences in fish assemblages along a gradient from freshwater to marine waters and to detect effects of habitat loss in the marginal areas of the estuary. Analyses in the sediment (granulometry, organic matter, dissolved oxygen) and water (dissolved oxygen, temperature, salinity and pH) in samples with different levels of habitat loss. We identified three categories of habitats and correlated with parameters of fish assemblages (density, biomass, richness, length and trophic guilds). A total of 77 species were recorded, forming two distinct fish assemblages, with family Eleotridae dominating in the upper, Gerreidae, Gobiidae and Tetraodontidae in the middle and lower estuary. Changes in the structure of fish assemblages as a reduction in density, biomass and richness were associated with habitat loss of natural features (muddy sediment replaced by sandy sediment, organic matter reduction). Dormitatus maculatus in upper estuary and Atherinella brasiliensis in the middle and lower estuary were the species that showed preference for the impacted areas and can serve as indicators of habitat loss due to silting marginal. / Salvador (BA)

Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2017-10-24T12:02:02Z No. of bitstreams: 1 PDF - Caroline Stefani da Silva Lima.pdf: 28204729 bytes, checksum: 5920971cb50b706bf8d83a493437825f (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2017-10-26T16:55:24Z (GMT) No. of bitstreams: 1 PDF - Caroline Stefani da Silva Lima.pdf: 28204729 bytes, checksum: 5920971cb50b706bf8d83a493437825f (MD5) / Made available in DSpace on 2017-10-26T16:55:24Z (GMT). No. of bitstreams: 1 PDF - Caroline Stefani da Silva Lima.pdf: 28204729 bytes, checksum: 5920971cb50b706bf8d83a493437825f (MD5) Previous issue date: 2017-02-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Estuaries are dynamic coastal ecosystems in which the interaction between the hydrological regime and the mixing of fresh and oceanic waters creates a gradient of variables that reflect on the structure of the fish community, as well as their spatio- temporal pattern. These characteristics are used as filters, that is, determining factors that select species ecologically similar, hence producing different groups of species along an environmental gradient. These filters can act on hierarchical scales, partitioning the diversity of species within the components α (local diversity), β (variation of diversity between sites) and γ (regional diversity). Therefore, the aim of this study was to analyze the composition, structure, hierarchical partitioning and if beta diversity is determined either by turnover or nestedness of fish assemblages in the Mamanguape river estuary, influenced by hydrological changes (rainy and dry periods). The composition and structure of the estuarine fish assemblages were characterized by a few dominant species in numerical abundance and biomass, being these considered core species. In addition, abundance and diversity increased with the proximity to the ocean due to adequate salinity conditions and greater habitat availability in these areas. The catch of fish in the estuary was higher during the rainy season, related to the recruitment period of many species that coincide with the environmental changes. The Canonical Correspondence Analysis indicated salinity and chlorophyll-a as the main filters of the spatial distribution of fish assemblages, separating them along the three zones according to the osmoregulation capacity of each species and the availability of resources in the zones. In the analysis of the hierarchical partition of the fish assemblages, the dissimilarity of the species composition was higher in the upper level (β3), influenced mainly by the turnover in both hydrological periods, suggesting the importance of the environmental heterogeneity for the fish diversity in this estuary. / Estuários são ecossistemas costeiros dinâmicos cuja interação entre o regime hidrológico, entrada de água doces e oceânica cria um gradiente de variáveis ambientais que refletem na estrutura da comunidade de peixes, bem como no seu padrão de utilização espaço-temporal. Estas características ambientais podem atuar como filtros, ou seja, fatores determinantes que selecionam espécies ecologicamente similares, consequentemente produzindo diferentes grupos de espécies ao longo de um gradiente ambiental. Tais filtros podem agir em escalas hierárquicas, particionando a diversidade de espécies dentro dos componentes α (diversidade local), β (variação da diversidade entre locais) a γ (diversidade regional). Portanto, o objetivo desse estudo foi analisar a composição, estrutura, bem como, partição hierárquica e se diversidade β das assembleias de peixes é determinada por turnover ou aninhamento no estuário do rio Mamanguape – PB, influenciada pelas mudanças hidrológicas (período chuvoso e seco). A composição e estrutura das assembleias de peixes estuarinas foram representadas por poucas espécies dominantes em abundância numérica e biomassa, sendo essas considerada core species. Além disso, a abundância e diversidade aumentaram com a proximidade com o oceano, devido às condições adequadas de salinidade e maior disponibilidade de habitats nestas áreas. A captura de peixes no estuário foi maior durante o período chuvoso, relacionadas ao período de recrutamento de muitas espécies que coincidem com as mudanças ambientais. A análise de correspondência canônica indicou a salinidade e a clorofila-a como os principais filtros da distribuição espacial das assembleias de peixes, separando-as ao longo das três zonas em função da capacidade de osmorregulação de cada espécie e a disponibilidade de recursos nas zonas. Na análise da partição hierárquica das assembleias de peixes, a dissimilaridade da composição de espécies foi maior no nível superior (β), influenciada principalmente pelo turnover em ambos os períodos hidrológicos, sugerindo a importância da heterogeneidade ambiental para a diversidade de peixes nesse estuário.