Another essential protective level was parental look after the egg and younger

Another essential protective level was parental look after the egg and younger

Lates niloticus

Some cichlids are mouth-brooders, and in such cases the males, females or both carry the eggs to special brooding grounds. The parents eventually leave their young in nursery areas which are situated inshore. Welcomme (1964) has shown that juvenile Oreochromis variabilis migrate away from the sheltered nursery beaches when they are around 5.0cm total length. In both Lake Albert and Lake Turkana the young of prey-species use the cover of the sublittoral Ceratophyllum zone and the shallow lagoons in order to escape predation (Gee, 1969). Greenwood (1965) found that Protopterus aethiopicus spends much of its first year in the cover provided by the matted root systems of papyrus in Lake Victoria. Macan (1977) reported that Asellus on mud is at risk from predation by Sialis intaria (L) but amongst Elodea it is relatively safe from all predators.

Another important adaptation developed by prey-species is migration. Some species such as Barbus altianalis, Labeo victorianus and Schilbe mystus are potamodromous, moving up rivers to spawn. The young often remain upstream in shallow water where they are more likely to escape predation by large fish (Lowe McConnell, 1975). The majority of the fishes in Lake Victoria appear to be more demersal than pelagic (Kudhongania and Cordone, 1974), however, in order to partially segregate themselves from predators during periods of peak susceptibility, some Haplochromis species migrate vertically on a diel basis.

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