Ecologia Alimentar de Jupiaba Abramoides (Eignmann, 1909) e Jupiaba asymmetrica (Eignmann, 1908) em Igarapés da Bacia do Rio Urucu, Coari (AM)

Abstract

Historically, the knowledge of fish feeding in streams, including resource use and the influence of spatial and temporal components, has subsidized studies on the structure of these populations and investigations of biological interactions. The objective of this work is to verify the existence of feeding overlap between sympatric species of the genus Jupiaba (J. abramoides and J. asymmetrica) in four streams (EC01, EC02, EC03 and EC04) in the Urucu River basin, Coari (AM). ECOl and EC04 were characterized as lakes located in natural clearings, and EC02 and EC03 were characterized as continuous woodland. Two sampling times (Aug. and Nov./2006) occurred during the dry season, and one during the flood season (Apr./2007). Collections were made by blocking methods with three nets (lmm mesh) in two stretches of 10 m, using hand and trawl nets. We verified 55 stomachs of Jupiaba. abramoides and 45 of J. asymmetrica. Jupiaba asymmetrica presented as main items in the diet: fragments of exoskeletons (FOI = 57.78%; FP = 7%; AI = 6.11 %), Formicidae (FOI = 33.33%; FP = 6.13%; AI = 3.09%). Jupiaba abramoides presented as the main items in its diet: exoskeleton fragments (FOi = 42.22%; FP= 4.02%; AI = 20.73%), plant fragment (FOi = 40%; FP= 12.65%; AI = 61.86%), and Diptera larvae (FOi = 22.22%; FP = 1.60%; AI = 1.63%). It was found that by Levin's niche breadth method, J. asymmetrica is classified as a specialist (1.012), with a strong tendency to insectivory, compared toJupiaba abramoides which presented itself as a generalist consuming food of animal and plant origin (0.455). The result of the food overlap calculations was 0.28, evidencing the absence of food overlap between the two species.