Fish assemblage distribution along a stretch of neotropical urban river

The objectives of this study were to evaluate some descriptors of fish assemblages in different stretches of a Neotropical urban river, located in the municipality of Sorocaba, S & atilde;o Paulo, Brazil, and to evaluate possible differences between them and the influence of seasonality. Collections were carried out between June/2019 and February/2020. The results obtained in relation to the physical and chemical variables of the water indicate that this is a river with the urban river syndrome and that seasonality has a relevant influence. The fish assemblage showed homogeneity in relation to richness and differences regarding diversity, dominance, and abundance in the stretches of the river studied. The multivariate ANOSIM analysis confirmed that the dry and rainy months are not similar to each other in terms of fish composition. The canonical correlation analysis explained 85.58% of the total data variation, indicating that water temperature and rainfall are important factors that influence species composition. It was concluded that the descriptors of the fish community in the studied stretches (richness, abundance, diversity, and dominance) undergo changes due to seasonal variations, which in urban rivers can be amplified, due to the consequences of the loss of vegetation cover, increased soil impermeability, reduction in the water infiltration rate, surface runoff, and maximum flows.