Preliminary gut content and dentition analysis reveal subtle resource partitioning and feeding adaptations within a haplochromine cichlid community of Lake Victoria satellite lake

Abstract

The trophic relationships between six haplochromine cichlids of Lake Kanyaboli, a satellite lake of Lake Victoria that has not been infested by the Nile perch (Lates niloticus), were studied as a first step towards understanding the cichlid community structure in this threatened wetland ecosystem. Coefficient of similarity analysis of diet revealed subtle trophic resource partitioning within this haplochromine community. Trophic specializations are further revealed by differences in dentition structures. Of the six haplochromine species examined, Astatotilapia nubila and Astatoreochromis alluadi had the highest coefficient of similarity (0.5256±0.300), indicating highest diet overlap, while Astatotilapia ‘big eye’ and Xistichromis phytophagus were the most ecologically separated (0.0210±0.019). Resource partitioning is further enhanced by a diurnal spatial distribution of the six species within the lake. Overall, the haplochromine cichlid community of Lake Kanyaboli is characterized by a relatively high trophic diversity compared to Lake Victoria. Small water bodies (SWBs) thus present opportunities for conservation of trophic diversity threatened by introduction of exotics in the Lake Victoria basin.

Key words: Community structure, haplochromines, resource partitioning, satellite lakes, trophic ecology.