The Cichlid Fishes of Lake Malawi, Africa

Abstract of Publication

Thompson, A.B. 1999. Simulation of reproductive rate, prey selection and the survival of pelagic fish of the African Great Lakes. Hydrobiologia 407: 207-218.  

Populations of two prey groups of pelagic mainly zooplanktivorous fish with differing life history strategies, were simulated with a Lotka-Volterra model with predation. Group r fish are r-selected species and have a high rate of biomass increase. These comprise of [sic] the small pelagic cyprinids of Lakes Malawi and Victoria and the clupeids of Lake Tanganyika. Group K fish are K-selected species and have a lower intrinsic rate of biomass increase. These comprise of [sic] the haplochromine cichlids of Lakes Victoria and Malawi. Piscivorous cichlids and Lates spp. form the predators. The model shows that the different rates of increase of the two prey groups and the relative predation pressure upon them, determines the equilibrium biomasses. The cyprinid/clupeid Group r fish only have a high biomass when heavy predation reduces the cichlid Group K fish populations. This is because more food is available to Group r fish, as well as a reduction in predation pressure from the piscivorous cichlids. Group K cichlid fish only have a high biomass when predation pressure is low. This occurs when adult zooplanktivorous cichlids are too large too be eaten by predators.




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