Distribution pattern of two fish species in a coastal stream in southeast Brazil.
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.
Mazzoni
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Universidade do Estado do Rio de Janeiro, Instituto de Biologia Roberto Alcântara Gomes/Ecologia, Rua São Francisco Xavier, 524, Maracanã, CEP 20550-013, Rio de Janeiro, RJ, Brazil.
Iglesias-Rios
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D000818:Animals; D001938:Brazil; D003247:Conservation of Natural Resources; D004777:Environment; D005399:Fishes / Q000502:physiology*; D005618:Fresh Water; D011156:Population Density; D011157:Population Dynamics