Fish habitat use in the Upper Beni mountain streams (Amazon Basin, Bolivia)

Abstract

The fish-habitat relationship was studied in 12 streams from the upper Beni River (La Paz Department, Bolivia) to test if the common species showed habitat preferences and to describe habitat use guilds. Fishes were caught in 181 fishing points of 10 to 20 m2. In each plot water velocity, water depth, and substratum size were estimated. The 41 taxa found in the 12 streams were grouped in four guilds differentiated according to water velocity (Limnophilic, Intermediate-Lentic, Intermediate-Rheophilic and Reophilic). In two guilds, the water depth also differentiated two subgroups. A Canonical Correspondence Analysis showed a significant relationship between fish guilds and the three environmental parameters. The most limnophilic and rheophilic guilds showed a higher dependence on habitat condition. In these mountain streams, the fish community is dominated by rheophilic fishes that represent 75% of the total abundance.