REPRODUCTIVE AND FEEDING BIOLOGY OF THE NATAL MOUNTAIN CATFISH, AMPHILIUS-NATALENSIS (SILURIFORMES, AMPHILIIDAE)

Aspects of the biology of the Natal mountain catfish, Amphilius natale nsis, including gametogenesis, spawn spawning season, size-at-maturity , sex ratio, diet and feeding morphology were determined from fish col lected in the Songimvelo Game Reserve, South Africa, between 1989 and 1990. Female sexual maturity was established at 63 mm total length. A, natalensis is an asynchronous, iteroparous spawner, breeding througho ut summer from August to February. Sex ratio of females to males was 2 .2:1, with females attaining a significantly larger size than males. G ametogenesis followed a pattern similar to that of other freshwater te leosts peaking over the spawning period. Stomach content analysis and observations on feeding morphology revealed that A. natalensis was an opportunistic predator with large fish consuming larger prey from a gr eater variety oi taxonomic groups. The most abundant prey items eaten were dipteran (particularly Chironomidae) and ephemeropteran(particula rly Baetidae) larvae.