2018-11-272018-11-272018-01-25SIQUEIRA, Alexandre Sampaio de. Padrões de co-ocorrência entre pares de espécies da ictiofauna de uma ria fluvial afogada da Amazônia Oriental. Orientadora: Solana Meneghel Boschilia. 2018. 35 f. Trabalho de Curso (Bacharelado em Oceanografia) - Faculdade de Oceanografia, Instituto de Geociências, Universidade Federal do Pará, Belém, 2018. Disponível em: http://bdm.ufpa.br/jspui/handle/prefix/851. Acesso em:.http://bdm.ufpa.br/jspui/handle/prefix/851Null models and co-occurrence indexes have been used in the last few decades to evaluate the behavior of communities. The aim of this study was to identify segregation patterns between ichthyofauna species pairs of to represent the spatial distribution in the community. In order to do so, we: i) compared the segregation pattern of the pairs of species of the rivers and bays; ii) described segregation, co-occurrence and random interactions between species pairs; iii) showed the relation of a possible pattern of segregation between pairs of species and the trophic guild of the species; iv) investigated if the abiotic parameters present significant variations in the periods (dry and rainy), and being: temperature, pH, Conductivity and water transparency. The sampling occurred in rivers and bays in lower Anapu river, in 2004, during the dry and rainy season. The assemblage was sampled using sets of gill nets (3-12 cm). Each sampling site physico-chemical variables were measured. A presence/absence matrix was created and applied the C-Score index, which measure the species pairs segregation of the assemblage. Considering all the sampling sites, the assemblage was spatially organized. Species co-occurrence were random when considering only the rivers while we detected values greater than expected by chance were found in bays. The distribution pattern was related to the geological evolution of the Caxiuanã as well as the behavior of the species in search for resources. It was possible to observe that different guilds have positive (segregation) and negative (co-occurrence) interactions. When random interactions occurred to the same guild, it was signaled that no pattern of segregation or co-occurrence was detected by the index. However we believed it was due to searching of resources at different depth strata, not to competition. Despite lower Anapu river being classified as a homogeneous region, not presenting great variation in temperature and water transparency, we observed significant differences to these variables between dry and rainy season. Therefore, the null models associated to co-occurrence index are useful tools in search for spatial distribution patterns besides the interaction analysis interpretation, promoting a greater knowledge on detected pattern by the C-Score index.Acesso AbertoPeixe de água doceDistribuição geográficaRio Anapu - PAAmazônia OrientalCNPQ::CIENCIAS EXATAS E DA TERRA::OCEANOGRAFIATrabalho de Curso - Graduação - Monografia