Trophic relationships in fish assemblages of Neotropical floodplain lakes: selectivity and feeding overlap mediated by food availability

ABSTRACT. The relationships between the degree of dietary overlap and food availability, and implications for food selectivity of fish species were evaluated at floodplain lakes on the upper Parana River floodplain. The hypothesis tested were: i) species become less selective in lakes with high availability of food resources; ii) species present higher food overlap in conditions of high availability of food resources; and iii) individuals of the species, become less specialized, in this case the food overlap will be high in conditions of more availability of food resources. In general, with the results was observed that species become less selective when the environment provided higher availability of food resources. Interspecific overlap did not show a pattern when evaluating availability of food resources in the lakes. However, intraspecific overlap tended to be more accentuated in conditions of high availability of resource food.