Distribution pattern of two fish species in a coastal stream in Southeast Brazil

Abstract

Longitudinal distribution of Mimagoniates microlepis and Hoplias malabaricus was analyzed in a coastal stream system in Southeast Brazil. Six sites were sampled by electrofishing in seven months, from July 94 to July 95. Densities of M. microlepis, and H. malabaricus and its prey (Poecilia vivipara, Deuterodon sp. and Astyanax janeiroensis) were estimated by the Zippin method; environmental variables of: (i) kind of substratum; (ii) percentage of pools, runs, riffles, instream vegetation, and canopy were registered for each site in each sampling month. The relative importance of each biotic and abiotic variable was tested through simple correlation analyses. We verified that M. microlepis occurrence correlates with canopy; H. malabaricus is correlated with instream vegetation, pools, clay substratum, and P. vivipara densities; and P. vivipara correlates with pools and clay substratum. Our results suggest that environmental variables, and food and shelter availability are the main factors in determining M. microlepis and H. malabaricus distribution.

Feeding ecology of Serrapinnus notomelas (Characiformes: Cheirodontinae) in small forest streams in the Machado River basin, Rondônia, Brazil

“…The fact that many species are restricted to areas with canopy cover has been attributed to input of greater amount of allochthonous material, particularly terrestrial insects (Mazzoni and Iglesias 2002). Thus, the great consumption of autochthonous items by S. notomelas may also be related to the reduced vegetation cover in the observed streams.…”

Aspectos da alimentação de Bryconamericus microcephalus(Characiformes, Tetragonopterinae) no córrego Andorinha, Ilha Grande – RJ

“…Por ser um ambiente densamente coberto por vegetação de grande porte, tem-se uma área sombreada com reduzida produção primária. Com isso, os exemplares coletados possuem dieta predominantemente composta por insetos de origem autóctone e alóctone fato que, no entanto, não descarta a possibilidade de se alimentarem de matéria vegetal em outro trecho do rio, visto tratar-se de uma espécie migradora e oportunista (Mazzoni & Iglesias, 2002); isso explicaria o QI típico de espécie onívora. Russo & Hahn (2001) verificaram que em duas espécies do gênero de Bryconamericus havia importante segregação na utilização dos recursos alimentares, sendo que uma espécie consumia basicamente formas larvais de insetos enquanto que a outra consumia formas adultas de insetos.…”

Spatial variation of five co-existing siluriformes in an atlantic rain forest drainage

“…Cyprinodontiformes occurrence was correlated with environmental variables (Aranha and Caramaschi, 1997). Mazzoni and Iglesias-Rios (2002) found that canopy abundance determined the occurrence of M. microlepis while H. malabaricus densities were positively correlated to marginal vegetation and P. vivipara was correlated to the pools and clay substratum. Menezes and Caramaschi (1994; observed that the occurrence of juveniles of Hypostomus gr.…”