Introgressive hybridization of tilapias in Zimbabwe

Abstract

Three species of tilapia native to Zimbabwe, Oreochromis mossambicus, O. mortimeri and O. macrochir are not naturally sympatric, but because of transplantation they have been brought into sympatry. Allozymes of fish examined from Lakes Kariba, Kyle and Chivero showed evidence of introgressive hybridization. The data showed non‐random mating populations in Lakes Kariba and Kyle. All three reservoirs displayed individuals with intermediate principal component scores and hybrid index scores indicating hybridization.