RESUMO
This study analyzed the diet of seven small-sized fish species (Characidae) and assessed their use of food resources. The species were collected in 2001 from nine ponds with aquatic macrophytes in the Paraná river floodplain, Brazil. Astyanax altiparanae, Astyanax fasciatus, Hemigrammus marginatus and Moenkhausia intermédia consumed aquatic and terrestrial insects. Bryconomericus stramineus and Moenkhausia sanctaefilomenae co-dominantly ate insects and microcrustaceans, whereas Hyphessobrycon eques had microcrustaceans as their most important food resource. Overlapping feeding coefficients varied from intermediate (0.4-0.6) to low ( 0.4) for the majority of the combination pairs. A high mean intestinal length was verified for A. altiparanae and A. fasciatus, while a smaller mean was found for H. eques. When comparing all these results, it is possible to conclude that the species were partially segregated by the trophic niche dimension. Thus, the co-existence and higher abundance of these small fish in the shoreline of the ponds is explained by high feeding adaptability, absence of specializations in the feeding tract (except intestinal length) and the wide food supply provided by aquatic macrophytes.
RESUMO
This study analyzed the diet of seven small-sized fish species (Characidae) and assessed their use of food resources. The species were collected in 2001 from nine ponds with aquatic macrophytes in the Paraná river floodplain, Brazil. Astyanax altiparanae, Astyanax fasciatus, Hemigrammus marginatus and Moenkhausia intermédia consumed aquatic and terrestrial insects. Bryconomericus stramineus and Moenkhausia sanctaefilomenae co-dominantly ate insects and microcrustaceans, whereas Hyphessobrycon eques had microcrustaceans as their most important food resource. Overlapping feeding coefficients varied from intermediate (0.4-0.6) to low ( 0.4) for the majority of the combination pairs. A high mean intestinal length was verified for A. altiparanae and A. fasciatus, while a smaller mean was found for H. eques. When comparing all these results, it is possible to conclude that the species were partially segregated by the trophic niche dimension. Thus, the co-existence and higher abundance of these small fish in the shoreline of the ponds is explained by high feeding adaptability, absence of specializations in the feeding tract (except intestinal length) and the wide food supply provided by aquatic macrophytes.
RESUMO
Diet and feeding activity of Leporinus amblyrhynchus before, during and after the damming of the rio Corumbá (Goiás State March 1996 to February 1998) were investigated. The diet, evaluated using the Feeding Index (IAi), showed that this species presents an invertivore feeding habit, preying on basically Chironomidae larvae. The feeding activity, estimated using the quantity of food in the stomach during a 24-hour cycle, showed that the feeding occurs mainly in the daytime. Considering the feeding aspects of this species during the formation of the reservatório of Corumbá there were small variations in the parameters (diet and feeding activity) dealt in this study.
Neste estudo, foram avaliadas a dieta e atividade alimentar diária de Leporinus amblyrhynchus, antes, durante e após o represamento do rio Corumbá, GO (março 1996 a fevereiro 1998). A dieta, avaliada pelo Índice Alimentar (IAi) mostrou que esta espécie apresenta hábito alimentar invertívoro, consumindo basicamente larvas de Chironomidae. A atividade alimentar diária, estimada pela quantidade de alimento nos estômagos, evidenciou tratar-se de uma espécie basicamente diurna que forrageia preferencialmente nos períodos de maior intensidade luminosa. Tanto a alimentação quanto o comportamento na tomada do alimento aparentemente não foram afetados pelo impacto causado pelo represamento do rio Corumbá.
RESUMO
Diet and feeding activity of Leporinus amblyrhynchus before, during and after the damming of the rio Corumbá (Goiás State March 1996 to February 1998) were investigated. The diet, evaluated using the Feeding Index (IAi), showed that this species presents an invertivore feeding habit, preying on basically Chironomidae larvae. The feeding activity, estimated using the quantity of food in the stomach during a 24-hour cycle, showed that the feeding occurs mainly in the daytime. Considering the feeding aspects of this species during the formation of the reservatório of Corumbá there were small variations in the parameters (diet and feeding activity) dealt in this study.
Neste estudo, foram avaliadas a dieta e atividade alimentar diária de Leporinus amblyrhynchus, antes, durante e após o represamento do rio Corumbá, GO (março 1996 a fevereiro 1998). A dieta, avaliada pelo Índice Alimentar (IAi) mostrou que esta espécie apresenta hábito alimentar invertívoro, consumindo basicamente larvas de Chironomidae. A atividade alimentar diária, estimada pela quantidade de alimento nos estômagos, evidenciou tratar-se de uma espécie basicamente diurna que forrageia preferencialmente nos períodos de maior intensidade luminosa. Tanto a alimentação quanto o comportamento na tomada do alimento aparentemente não foram afetados pelo impacto causado pelo represamento do rio Corumbá.