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

Abstract

Feeding habitats and trophic overlap of the freshwater stingrays Potamotrygon falkneri e Potamotrygon motoro (Chondrichthyes, Potamotrygonidae) in the upper Paraná river floodplain, Brazil. 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.

Diet of the freshwater stingray Potamotrygon motoro (Chondrichthyes: Potamotrygonidae) on Marajó Island (Pará, Brazil)

“…The feeding studies in continental stingrays have shown variations in composition and frequency of certain food items, as well as intra and inter-specific diet differences according to Some aspects of the feeding habits and diet of Potamotrygon motoro were previously studied by other authors using varying methodologies (Pântano-Neto and Souza, 2002;Lonardoni et al, 2006;Melo et al, 2007;Shibuya et al, 2007;Silva and Uieda, 2007). Results from these researchers demonstrated that this species has feeding plasticity and diet variability.…”

Catfishes as prey items of Potamotrygonid stingrays in the Solimões and Negro rivers, Brazilian Amazon

“…Potamotrygon motoro seems to be predominantly insectivorous in the Cristalino (a tributary of the Araguaia River) and Paraná rivers (Pantano-Neto 2001, Lonardoni et al 2006, Silva & Uieda 2007, while individuals inhabiting the Negro River take crustaceans as their most important prey, followed by teleosteans (Shibuya et al 2009). In addition, Almeida et al (2010) and Vasconcelos & Oliveira (2011) also showed the occurrence of teleosteans, including catfishes, in the diet of potamotrygonid stingrays.…”

“…Potamotrygonidae stingrays consume a wide variety of prey, feeding on insects, mollusks, crustaceans, and teleosteans (Lasso et al 1996, Lonardoni et al 2006, Rincon-Filho 2006, Silva & Uieda 2007, Shibuya et al 2009). Their diets may be directly related to the availability of any given prey, and some species display specific dietary habits [e.g.…”

The more stirring the better: cichlid fishes associate with foraging potamotrygonid rays

“…Although not much probable, one explanation could be that the rays prey occasionally on small characids (Lonardoni et al, 2006;Garrone-Neto, 2009). However, further field studies may disclose additional associations of fishes other than cichlids and even other aquatic animals with foraging freshwater rays.…”