Browsing by Author "Bwaku, Wandera Sylvester"

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    The feeding and breeding patterns of some paedophagous Haplochromis species from Lake Victoria
    (University of Dar es Salaam, 1987) Bwaku, Wandera Sylvester
    This study investigates the feeding and breeding patterns of the paedophagous Haplochromics species in the Mwanza area of Lake Victoria. Depth distribution of these fishes is also studied. Specimens of H. microdon, H. microobesus, H. black cryptodon, H. parvidens, the obesus complex and the cryptodon complex were caught, mostly by bottom trawling, and analysed. Juveniles fed mainly on zooplankton (copepods and cladocerans) and insects while adults ate eggs and buccal stages of cichlid larvae. With the exception of H. microobesus which showed a seasonal diet change from paedophagy to zooplankton, the rest of the paedophages studied ate eggs and fish larvae throughout the year, increasing the amounts of supplementary food items (zooplankton and insects) during the time when eggs and fish larvae are in short supply. Algae (mainly Melosira sp.) were eaten by all species during the bloom but simply as a supplement to the major food items, eggs and fish larvae. H. black cryptodon and the obesus complex were found to breed throughout the year, the latter showing a peak in the rainy season while the former showed peak breeding activity immediately after the rains. Other species which showed peak breeding during the rainy season were H. microdon, H. microobesus and the cryptodon complex. H. parvidens was found not to breed during this period of heavy rains when all other paedophages are breeding but bred throughout the rest of the year. H.microobesus and H. parvidens were found to extend into the deeper waters of the main lake while H. microdon and H. black cryptodon were restricted to the shallower littoral and sublittoral waters of less than 15metres depth