Genetic Diversity and Differentiation of Oreochromis mossambicus (Peters, 1852) Inferred from Combined Mitochondrial DNA Markers (COI + D-Loop) in Limpopo Province, South Africa

The native Mozambique tilapia (Oreochromis mossambicus) serves as a cornerstone for aquaculture development in Limpopo Province, South Africa. Its adaptability to diverse culture systems, including backyard farming, highlights its potential to address food insecurity and poverty in rural communities. However, the long-term sustainability of this initiative depends on the genetic health and management of the cultured populations. This study investigated the evolutionary history, genetic diversity, and differentiation of O. mossambicus across five localities in Limpopo Province (Cordier reservoir, Nandoni reservoir, Mall of the North pond, University of Limpopo pond, and Polokwane Farm) using the combined mitochondrial DNA (COI + D-loop) dataset. Phylogenetic analysis revealed monophyly, with three well-supported clades. There was evidence of genetic affinities among some individuals within the five localities, supported by low genetic variation among populations and a common haplotype shared across all five localities. The Mall of the North population showed no genetic variation (Hd = 0.00; π = 0.00), indicating high homogeneity, whereas Nandoni exhibited the highest diversity (Hd = 0.83; π = 0.01), suggesting its potential as a primary broodstock source. These findings provide an important genetic baseline for farmed O. mossambicus, offering essential information for sustainable aquaculture management and conservation planning in the province.