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Hábitos alimentares e sobreposição trófica das raias <em>Potamotrygon falkneri</em> e <em>Potamotrygon motoro</em> (Chondrichthyes, Potamotrygonidae) na planície alagável do alto rio Paraná, Brasil

2007; Editora da Universidade Estadual de Maringá (Eduem); Volume: 28; Issue: 3 Linguagem: Inglês

10.4025/actascibiolsci.v28i3.208

1807-863X

Alessandra Pasian Lonardoni, Erivelto Goulart, Edson Fontes de Oliveira, Milza Celi Fedatto Abelha,

Fish Biology and Ecology Studies

Feeding habits and trophic overlap of freshwater stingrays Potamotrygon falkneri e Potamotrygon motoro were evaluated in the upper Paraná river floodplain. Samples were collected during periods of drought (August/2004) and flood (January/2005) near Mutum island. Fishhook, harpoon and long line were used to capture the individuals and a total of 49 stomach contents of P. falkneri and 16 of P. motoro were analyzed. Diet composition was analyzed by the relative occurrence and volumetric frequencies. The trophic overlap was quantified by the index of niche overlap of Pianka. Results indicated that both species predominantly consumed mollusks during the flood season, while in the drought season the diet of P. falkneri was composed mainly by fish and P. motoro for aquatic insects. The values of the index of niche overlap varied from 0.38, in drought (moderate), to 0.94 in flood (accentuated). The seasonal variation of the composition of the diets was attributed to fluctuations in the availability of food resources in the floodplain.