Index). Spearman correlation analysis, a glm and CCA were performed between biotic and abiotic variables, and we used the CPUE as a measure of fish abundance. Results: Eleven taxa of fish were recorded, four of which were predated by adult "trahira". Insects and other items were also common in the stomachs of juveniles. According to statistical analysis, it was observed that the highest consumption of cichlids was correlated with its increase in CPUE in the environment, while no relationship was observed for A. bimaculatus, C. bimaculatum and S. notonota abundances. The environmental factors as nutrients, transparency and water volumn were related to selection of species by trahira. Conclusions: Intrinsic characteristics of preys as swimming speed, food habit and the food preference of the predator possibly be the main factors to selection of species. Other mechanisms as heterogeneity of habitat and environmental factors can also influence the consumption of prey by trahira.

AimTo determine the composition and biomass of functional groups around the vertical and temporal gradient correlated with environmental conditions and apply the index Q in a water-supply reservoir.MethodsWater samples were collected monthly (n = 92) between 2009 and 2011 in two points of the dam for physicochemical and biological analysis.ResultsThe pH, dissolved oxygen and water temperature showed significant differences between the photic and aphotic zones (p<0.05). The vertical variation of dissolved oxygen and water temperature, showed a profile of stratification. The phytoplankton community was represented by 11 functional groups: S1, M, H1, Lo, P, F, SN, J, W2, MP and R.ConclusionsThe vertical variations were less pronounced than the temporal variations in the phytoplankton community. The Q index pointed out poor water quality, corresponding to the current state of eutrophication in the reservoir and it was sensitive to responsive to environmental and hydrodynamic changes in these systems, demonstrating to be an appropriate tool for monitoring and evaluating the quality of water in tropical semi-arid reservoirs.

ResumoAs regiões semiáridas do Nordeste brasileiro sofrem com os prolongados períodos de estiagem, afetando a qualidade da água e a produtividade pesqueira. Os estudos têm demonstrado que as alterações entre períodos de chuva e estiagem têm profundas influências sobre os organismos dos ambientes aquáticos das regiões semiáridas e em especial sobre a ictiofauna. Apesar disto, poucos são os estudos que tentam conhecer e elucidar a ecologia de peixes do semiárido. O objetivo do presente artigo foi conhecer a diversidade e alguns aspectos da estrutura populacional de espécies de peixes, a fim de avaliar a importância da formação das poças para a conservação das espécies e da produtividade pesqueira. Foi encontrado um total de 13 espécies de peixes, das quais uma espécie é exótica (Oreochromis niloticus). A abundância de espécies foi altamente variável entre os meses de coleta, embora a riqueza tenha revelado baixa flutuação. As espécies de importância econômica apresentaram tamanho médio acima de 7cm de comprimento padrão e 57,9% dos indivíduos estiveram em atividade reprodutiva. Os resultados demonstraram que o período de estiagem afeta a comunidade de peixes, sendo que as poças parecem ser locais importantes para a conservação da diversidade e da produtividade pesqueira. AbstractFish diversity in pools of an intermittent river in a semiarid region of Paraíba, Brazil. Prolonged periods of drought cause alterations in water quality and productivity of fisheries in semiarid regions of Brazil. Changes between periods of rain and drought affect aquatic organisms, especially fish. However, there are few studies that have attempted to understand and elucidate the ecology of fish in these semiarid regions. The purpose of this study was to investigate the diversity, and some aspects of population structure of fish species in these areas, in order to evaluate the importance of shallow pond formations in the conservation of these taxa and the productivity of these fisheries. We recorded 13 fish species, of which one was exotic (Oreochromis niloticus). Species abundance was highly variable among months, while variability of richness was low. The average size of the fish, which is important for the local economy, was over 7cm long, and 57.9% of individuals were Revista Biotemas, 25 (3), setembro de 2012 162 M. M. L. Cardoso et al.reproductively active at the moment of capture. The results show that the dry season affects the structure of the fish community and that the pools are important sites for the conservation of the diversity and productivity of these fisheries.

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Role of the rain and macrophytes on temporal and spatial pattern of ichthyoplankton in the Caatinga Biome, Brazil Papel da chuva e das macrófitas no padrão temporal e espacial do ictioplâncton no Bioma Caatinga, Brasil