Composição taxonômica e distribuição espaço temporal da assembleia de larvas de peixes no reservatório de Curuá-Uma, Santarém, Pará
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2018-05-25Autor
SUZUKI, Maria Aparecida de Lima
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The objective of this work is to investigate the performance of the longitudinal gradient of the Curuá-Una reservoir on the taxonomic composition, abundance, diversity and richness of ichthyoplankton species, to analyze the spatio-temporal distribution patterns of fish larvae and their relationship with the variables environmental, as a way to subsidize management policies and strategies for the conservation of natural resources, aiming at maintaining the fish stocks of the region. The biological material was collected using a 300 μm mesh of plankton coupled with a flowmeter during April 2016 to March 2017 in 12 collection stations distributed between the fluvial, transition and lacustrine zones of the reservoir . Environmental variables were measured in loco. 3,864 fish larvae were recorded, recorded in 30 taxa classified in 8 orders, 16 families, 25 genera and 27 species. In the fluvial environment the highest density of fish larvae was observed, also presenting greater richness, diversity, abundance and equitability. Microphilypnus tapajosensis, Caires 2013 was the species that most contributed with number of individuals at all points (89%). In relation to seasonality, the highest densities occurred during the rainy season. Significant differences were observed only between river and lake environments. It was not possible to observe a distribution pattern of the larvae separating the environments in lacustrine, transition and fluvial zone through the distribution of the species (result of the NMDS), as well as there was no significant difference in species composition (presence / absence) among the areas (result of Permanova). The loss of species along the longitudinal gradient supports the hypothesis that the impact caused by the riverbeds affected the local ichthyofauna, demonstrating that the area needs mitigating actions.With high densities of fish larvae close to tributary confluence, it is possible to determine that these environments are used for spawning and development for many species of fish and the presence of larvae throughout the studied region shows that several larval groups of fish complete their cycle of life in the reservoir, mainly small-sized and short-range migratory species. Therefore, it is necessary to implement management actions that aim at the maintenance and conservation of these environments, and consequently for the community of fish larvae.
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