Feeding of introduced species of Cichla (Perciformes, Cichlidae) in Volta Grande reservoir, River Grande (MG/SP)

L M Gomiero,F M S Braga

doi:10.1590/s1519-69842004000500008

L M Gomiero, F M S Braga

Open Access

https://doi.org/10.1590/s1519-69842004000500008

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Abstract

Both species studied, Cichla cf. ocellaris and Cichla monoculus, fed mainly on fish, the first on Cichla spp., Plagioscion squamosissimus, and Tilapia rendalli, and the second, Cichla monoculus, on Cichla spp. Both diets indicated a strong correlation among the food items. Remarkable ontogenetic change was noted in both species diet: the young fed on crustaceans and insects while the adults fed mainly on fishes. The species studied, which are highly adapted to a brief life span, cause serious damage to the fish communities by predation, competition, and cascade effects throughout the whole trophic chain.

Highlights

Dam construction determines the course of river sectioning, in which running waters start to accumulate, resulting in lentic water masses
Gallery forest is destroyed by overflow and many resources used by the fish communities become scarce, with alterations in occupation and growth occurring in species of aquatic plants (Castro & Arcifa, 1987)
The average number and average weight of the preys ingested by both species revealed that for Cichla cf. ocellaris, the average number is high in the small classes

Summary

Introduction

Dam construction determines the course of river sectioning, in which running waters start to accumulate, resulting in lentic water masses. Intercalation of lentic environments along fluvial paths causes a fundamental transformation in hydrographic basins by changing hydrography, water quality, sedimentation, and aquatic life (Paiva, 1983). Gallery forest is destroyed by overflow and many resources used by the fish communities become scarce, with alterations in occupation and growth occurring in species of aquatic plants (Castro & Arcifa, 1987). Dams obstruct upstream migration of lotic fishes in addition to degrading habitats (LoweMcConnell, 1990). The Volta Grande Reservoir, located in a tropical area (48°25’-47°35’W, 19°57’-20°10’S), resulted from damming of the Rio Grande river approximately 25 years ago to produce electric energy. The result was a flooded area of 221.7 km with a volume of 2,268 km (Braga & Gomiero, 1997)

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