Aspectos da biologia alimentar de potamotrygon leopoldi (castex & castelo, 1970) (chondrichthyes: potamotrygonidae) na região do médio rio Xingu - Pará.

Abstract

Potamotrygon leopoldi is a freshwater ray that belongs to the Potamotrygonidae family. This species endemic to the Xingu River basin is highly valued as an ornamental fish. The present study is a contribution to the knowledge of this species, being the first on its feeding biology. Specimens were collected in the Xingu River in 2003 and 2004. Stomachs were analyzed (n=59). Items were identified to the lowest possible taxonomic category. Analyses indicated: Relative Frequency of Occurrence (%FO), Numerical Percentage (%N), Percentage by Weight (%P), Relative Importance Index (IRI and %IRI). Repletion and digestion were also observed. The results indicate that these rays feed on mollusks (Gastropoda), teleosts, crustaceans (Caridae/Brachyura) and insects. Some plant tissue fragments were also found. The level of repletion indicated that the stomachs had little content (58% with % repletion). The degree of digestion revealed poorly digested food items (62%). The data indicate a feeding preference for mollusks and fish. The specimens probably ingest their prey shortly before capture.