Resumo

RODRIGUEZ-OLARTE, Douglas  e  KOSSOWSKI, Christophe. Reproduction of fishes in flooding events of Portuguesa River, Venezuela. Bioagro [online]. 2004, vol.16, n.2, pp.143-147. ISSN 1316-3361.

The reproduction of fishes in flooding events in the Portuguesa River, Venezuela, is reported. In the high plainlands (about 100 meter above sea level) and only at specific water speeds (higher than 0.59 m/s) eggs presenting embryonic stages between the four-cell-embryo and the phase of independent movement of the embryo were collected, suggesting that reproductive events occurred in a specific section of river associated to the geomorphological transition from foothills to the high plainlands. The eggs were incubated in laboratory and it was obtained mainly species of Characiformes and Siluriformes which are migratory fishes that make local movements of ascent and descent at the time of flooding. Two basic aspects in the reproduction of fishes during floods are considered: magnitude of the water flow and areas of flood downstream. The regional fluvial ecosystems are put under severe impacts (dams, deforestation) that affect the survival of great part of ichthyofauna that reproduces during events of flooding. A special management of the section of the Portuguesa River is suggested where the reproductive events take place.

Palavras-chave : Migratory fishes; Characiformes; Siluriformes.