Diet of fishes in Passa Cinco stream, Corumbataí River sub-basin, São Paulo state, Brazil

The aim of this study was to describe and classify the food preference of fish species in Passa Cinco stream. The grade of feeding preference was applied to stomachs considered replete. This method consists of attributing values to food items found in certain species, according to the participation of each item in the analysed stomach. We analysed 576 full stomachs of 28 species. The autochthonous insects were the main constituents of the diets of these species, and the majority of ingested items classified as occasional. Allochthonous items such as plant debris, seeds and earthworms were associated with higher-order site. Of the total possible combination pairs of species, 29.4% showed high overlap, wich occurred mainly within species that consumed aquatic insect larvae. However, those species showed significant differences in the exploitation of food resources. Omnivory was common, showing the plasticity of the required species that inhabit environments as found in streams

Fish distribution in watersheds of the eastern part of the Serra da Mantiqueira (state of São Paulo)

The present work aims to analyse jointly four contiguous watersheds in the eastern part of the Serra da Mantiqueira with respect to the distribution of fish fauna and physical structure. The watersheds of Piracuama river, Ribeirão Grande, Buenos and Guaratinguetá are located in Pindamonhangaba, Campos do Jordão and Guaratinguetá municipalities, in the state of São Paulo. Data were collected between the years 2001 and 2010, with collections distributed throughout the seasons, including sites located on the slope and piedmont. The limnological parameters analysed were different between watersheds and habitat structure was different only for the slope segments between Ribeirão Grande and Buenos watersheds, and between Ribeirão Grande and Piracuama watersheds. Thirty-five species of fish were caught, with the highest species richness found in the Ribeirão Grande watershed (30 species), followed by the Piracuama (23 species) and Buenos and Guaratinguetá (21 species each). The most abundant species in both the segments (slope and piedmont) was Trichomycterus itatiayae. The highest degree of species dominance occurred in the Guaratinguetá watershed and in the segment slope, being T. itatiayae the dominant species. Species diversity was lower at the slope than the piedmont, indicating variability in species abundance. Again T. itatiayae was the most abundant species in both segments, showing to be a well adapted species to these streams systems by presenting, as well as other species, morphological adaptations to the stream environment

Composition and structure of fish assemblage from Passa Cinco stream, Corumbataí river sub-basin, SP, Brazil

The aim of this work was to determine the composition of the fish assemblage of Passa Cinco stream and verify changes in their structure on the altitudinal gradient. Six samples were performed at five different sites in Passa Cinco stream (from the headwater, at order two, to its mouth, at order six), using an electric fishery equipment and gill nets in May, July, September and November of 2005 and January and March of 2006. The indices of Shannon's diversity, Pielou's evenness and Margalef's richness were quantified separately considering the different fishery equipment (nets versus electric fishery equipment). An ANOVA was used to compare samples collected in relation to values of abundance, diversity, evenness and richness. The representativeness of the species was summarised by their average values of abundance and weight. We captured 5082 individuals distributed into 61 species. We observed a trend of increasing diversity, richness and evenness of species from site 1 to 3, with further decrease in sites 4 and 5. The values found for habitat diversity also followed this pattern. Significant differences were found for all three indices considering the electric fishery samples. For individuals caught with nets, only the richness index showed a significant difference. Characidium aff. zebra was an important species in the headwater and transition sites and Hypostomus strigaticeps in middle-lower course sites. Despite the small extension of the Passa Cinco stream, environments structurally well defined were evidenced by the species distribution and assemblage composition along the gradient