Diet of Pimelodella laticeps (Siluriformes: Heptapteridae) in La Choza small stream, Buenos Aires, Argentina

MAROÑAS, M. E.; SENDRA, E. D.; BRANCOLINI, F.

St. Louis, Missouri,

Simposio; 2nd International Catfish Symposium. Conservation, ecology, management; 2010

Diet of Pimelodella laticeps (Siluriformes: Heptapteridae) in La Choza small stream, Buenos Aires, Argentina.   As part of the project “Global changes in river systems: effects on biodiversity, food web and system functioning (GLOBRIO)”, the diet of P. laticeps was studied. This species has a permanent presence and is one of the dominant taxa of the fish community. Despite its importance, both in lotic and lentic environments in Argentina, little is known about their food habits. The sampling was conducted in spring 2007in two sites with different environmental characteristics. The analysis was carried out on the anterior third of the digestive tract of 40 specimens. In each stomach food items identified taxonomic determination was conducted as accurately as possible. For each sampling site was calculated the frequency of occurrence and weight percentages. Weight per item was obtained for the pool of stomachs contents. The analysis was completed with a measure of the feeding importance. According to feeding habits, P. laticeps corresponds to a kind associated with the benthos and the surface film of water, markedly carnivorous in both sampling sites. The results of this study agree with those obtained for the population of Chascomús shallow lake (Buenos Aires, Argentina). Based on frequency of foods identified, the composition of the diet agrees in that it is very diverse and as to the low trophic niche fidelity exhibited by the species.