Feeding ecology of the siluriform Pimelodella laticeps Eigenmann, 1917 in a Pampean stream from Argentina

SOLARI LÍA; GARCÍA MIRTA; GARCIA DE SOUZA JAVIER RICARDO

Revista del Museo Argentino de Ciencias Naturales nueva serie

Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"

Lugar: Ciudad Autónoma de Buenos Aires; Año: 2017 vol. 19 p. 211 - 223

1514-5158

Pimelodella laticeps Eigenmann, 1917 is the most abundant siluriform in the El Pescado Stream, located in thedepressed region known as pampean region (Buenos Aires, Argentina). To characterize its feeding habits in this environment, weanalyzed the dietary contents on seasonal samplings from May 1991 through August 1993. To evaluate the relative contributionof the different dietary components, the index of relative importance (IRI) was used. Pimelodella laticeps preferred sectors withaquatic macrophytes, and predated mainly on organisms from the periphytic and benthic communities. The main food was cyclopoidcopepods, which taxa usually have littoral or benthic habitats, and only to a lesser extent are components of the planktoncommunity. The planktonic organisms available in the environment were analyzed by the Olmstead-Tukey-test, which diagramindicated that the dominant items were copepods, ostracods, and chironomids. Chydorid cladocerans, harpacticoid copepods,mayfly larvae, and amphipods also became dominant but less frequently. To understand the feeding strategies of P. laticeps, thefish diet was compared with the available plankton as analyzed by a nonparametric multivariate analysis (permutation-basedone-way ANOSIM). Pimelodella laticeps consumed almost no phytoplankton, while the discriminating items from the latterassemblage were identified as having high values in the environment.