Mitochondrial DNA Analysis Uncovers Widespread Population Bottleneck in Smooth‐Head Catfish, <scp> <i>Clarias liocephalus</i> </scp> (Boulenger 1898) of Lake Victoria Basin, Kenya

ABSTRACT Although Clarias species are increasingly important in East Africa for aquaculture and biodiversity, their species biodiversity is poorly documented and therefore natural populations suffer overexploitation, with few conservation measures. Genetic diversity is critical in identifying such populations, to inform the formulation of suitable conservation measures. Mitochondrial DNA sequences of 402 base pairs from the D‐loop region were used to assess genetic diversity and population structure of the smooth‐head catfish, Clarias liocephalus , the most widely distributed small‐sized clariid catfish species of the Lake Victoria Basin of Kenya. A total of 27 haplotypes were identified from sequences of 237 fish. Lake Kanyaboli exhibited the highest number of haplotypes, while Yala River and the University of Eldoret reservoir had the fewest, with one each. Haplotype diversity was greatest in Lake Kanyaboli and lowest in the Yala River samples. Samples from the nine sites grouped into eight clusters. F ST pairwise comparisons indicated fish from eight sites were distinct populations, whereas the University of Eldoret reservoir and the Nzoia River Basin were similar ( p &gt; 0.05). Controlled fishing effort, especially for riverine populations, to address overexploitation, as well as controlled sand harvesting and deforestation to minimize habitat destruction may improve the conservation of C. liocephalus of Lake Victoria basin, Kenya.