Feeding of holoshesthes Heterodon eigenmann (Teleostei, Cheirodontinae) of the cajuru reservoir (Minas Gerais, Brazil), in relation to the vegetal biomass on its depletion zone (original) (raw)

1998, Revista Brasileira de Zoologia

Stomach contents of Holoshesthes heterodoll Eigenmann, 1915 (Teleostei, Cheirodontinae), collected in the depletion zone ofCajuru reservoir when it was at its maximum water levei in two stations with different vegetal densities, were studied in order to investigate the influence ofthe flooded vegetal biol11ass on the food quantity and quality ingested by fi sh. Eighteen individuais from each station were examined. The standard length was 1.53±O.05 cm and 1.52±O.05 cm, respective1y at the lower biomass (8.19 kg dly weightJha) and higher biomass (38.10 kg dly weightJha) sampling stations. The stomach repletion Index (SRl) was applied for the quantitative ana1ysis. The alimentmy index (IA i) was used for the quali-quantitative analysis, with the volume of the items obtained through the points method. SR! did not show values significatively difterent between the two stations, p::::O.05 , by applying the Mann-Whitney test. ln both situations, Cladocera was the most important item. There were no correlation between the flooded vegetal biol11ass in lhe depletion zone and lhe intake of food by H. helerodon. However, as there were no empty stomachs, possibly even the lower vegetal biol11ass was enough to provide abundant feeding resources. KEY WORDS. Fish feeding, reservo ir, depletion zone, water leveI, vegetal biomass,