The diet of largemouth bass, Micropterus salmoides, in Lake Naivasha, Kenya

Abstract

Lake Naivasha is a freshwater lake situated in the eastern rift valley of Kenya. Only five species of fish are present, all of which have been introduced. Of these, Oreochromis leucostictus, Tilapia zillii and Micropterus salmoides (largemouth black bass) support an important gillnet fishery with bass also being taken for sport. Until bass reached 260 mm f.l. they depended upon invertebrate food organisms. Thereafter crayfish, fish and frogs became increasingly important the larger the size of the bass. The most important invertebrate prey species was the water boatman, Micronecta scutellaris, followed by chironomid and culicid pupae. Zooplank‐ton was consumed but only in large quantity by fish smaller than 80 mm. For bass over 260 mm the crayfish, Procambarus darkii, was the principal food. The largemouth bass in Lake Naivasha are generalized macro‐predators, feeding principally on free‐living animals of a kind most likely to be found in the littoral zones.