THE REPRODUCTIVE AND FEEDING BIOLOGY OF SCHILBE INTERMEDIUS RUPPELL IN THE OKAVANGO DELTA, BOTSWANA

The reproductive and feeding biology of 314 Schilbe intermedius Ruppel l 1832 collected in the Okavango Delta, Botswana, between April 1985 a nd February 1986 during low, intermediate and high water level were in vestigated. S. intermedius matures at 130 mm standard length and is a monocyclic spawner. Females predominate in the population and have an average fecundity of 27107 eggs. In the northern riverine floodplain o f the Delta fish spawn in mid-summer during the peak flood. In the sou thern drainage rivers fish spawn in spring, which is two to three mont hs after the arrival of the winter flood waters. S. intermedius is an opportunistic predator with a diet consisting largely of fish 41%, aqu atic larvae 25%, terrestrial insects 14%, aquatic insects 7% and crust acea 5%. Juvenile S. intermedius feed predominantly on insect larvae, while adults are largely piscivorous.