Alimentacion de Pterodoras granulosus (Valenciennes) (Pisces, Doradidae) en la baja cuenca del Plata

Abstract

Feeding habits of Pterodoras granulosus (Valenciennes) (Pisces, Doradidae) in the lower Plata Basin. The feeding biology of Pterodoras granulosus (armored catfish) was studied in an extensive area comprising two environments of different characteristics, a typical lotic system, the Lower Paraná River, and an environment transitional towards an estuarian system on the right margin of the Río de la Plata. The relative importance of the different feeding items observed in the stomach content of Pterodoras granulosus represented the relative abundance of them in the environment. Therefore, P. granulosus appeared as a benthic, strongly euriphagic and hardly selective organism consuming vegetation and molluscs, whith little selectivity, its diet being dominated by vegetation in the Lower Paraná River and molluscs on the right margin of the Rio de la Plata. The mussel Limnoperna fortunei showed a high percentage of occurrence in all sampling sites. The eventual importance of the feeding habits of P. granulosus on the population density of C. limnoperna is discussed.