| Journal: | Brazilian journal of biology |
| Database: | PERIÓDICA |
| System number: | 000276084 |
| ISSN: | 1519-6984 |
| Authors: | Nunes, D.M1 Hartz, S.M |
| Institutions: | 1Universidade Federal do Rio Grande do Sul, Instituto de Ciencias Biologicas, Porto Alegre, Rio Grande do Sul. Brasil |
| Year: | 2006 |
| Season: | Feb |
| Volumen: | 66 |
| Number: | 1a |
| Pages: | 121-132 |
| Country: | Brasil |
| Language: | Inglés |
| Document type: | Artículo |
| Approach: | Experimental, analítico |
| English abstract | Oligosarcus jenynsii and Oligosarcus robustus are fishes of Characidae family that occur in Rio Grande do Sul, Uruguay and northern Argentina. This work purported to study the feeding dynamics (repletion and hepatosomatic indexes and condition factor) over time, and to investigate the coexistence of these two species by evaluating the partition of resources using qualitative and quantitative analyses of diet, temporal and spatial segregation throughout the water column and some ecomorphological aspects of the species in the Lagoa Fortaleza. Specimens were sampled monthly, from May 2000 to April 2001 during 24 h/month, using stationary gill nets of different mesh sizes. The records of each individual included total and standard length; total, stomach and liver weight; sex and stomach repletion. The variation of the mean values of repletion index and relative frequencies of stomach repletion stages indicate that O. jenynsii and O. robustus do not present seasonal differences in feeding intensity. The hepatosomatic index shows an allocation of energy to the liver during every period except reproduction, when part of the energy is used for gonad maturation. The estimated condition factor for both species reveals an increase in the reproductive period, evidencing the influence of gonads upon the condition of the fish. The diet analysis revealed that O. robustus is piscivorous, whereas O. jenynsii is a generalist carnivore, tending to piscivory as well. The active period of O. robustus is more concentrated at sunrise and sunset, whereas |
| Disciplines: | Biología |
| Keyword: | Ecología, Peces, Characidae, Oligosarcus jenynsii, Oligosarcus robustus, Alimentación, Morfología, Brasil |
| Keyword: | Biology, Ecology, Fish, Characidae, Oligosarcus jenynsii, Oligosarcus robustus, Feeding, Morphology, Brazil |
| Full text: | Texto completo (Ver HTML) |
