Habitat use and food partitioning of the fishes in a coastal stream of Atlantic Forest, Brazil

Abstract

We analysed the fish assemblage in the "Mergulhão" stream (southern Brazil) with underwater observations for habitat use, considering water depth, current velocity, bottom type, shadow from vegetation cover, distance of stream-edge, and vertical position. Stomach contents or foregut content samples of the most abundant species were collected from 26 species (10 families). The fish assemblage occupied the bottom stream. The similarity analysis of spatial occupation of species grouped four habitat use guilds: A) "lambaris" (Astyanax sp. and Deuterodon langei), Characidium spp. (C. lanei and C. pterostictum) and Rineloricaria kronei used the bottom in deep sites and waters with middle current; B) Pimelodella pappenheimi and Corydoras barbatus used the bottom in sites with lower current; C) Mimagoniates microlepis used the surface of the water column; and D) Phalloceros caudimaculatus used shallow sites and waters without current. Species with few records were analysed descriptively. Diet similarity suggested seven trophic guilds: Microglanis sp. and Pimelodella pappenheimi: omnivorous/carnivorous guild; Corydoras barbatus: omnivorous/insectivorous guild; Characidium lanei: aquatic insectivorous guild, mainly aquatic insects; Mimagoniates microlepis: terrestrial insectivorous guild, mainly terrestrial insects; Deuterodon langei and Astyanax sp.: omnivorous/herbivorous guild; Rineloricaria kronei, Kronichthys subteres, Schizolecis guntheri, Hisonotus leucofrenatus and Pseudotothyris obtusa: herbivorous guild; and Phalloceros caudimaculatus: algivorous guild. When the guilds were similar, the species were generalists in diet and in habitat use.