An assessment of genetic differentiation among feral Australian tilapia populations

Abstract

Feral populations in Australia of the introduced cichlid, tilapia, were compared by using cellulose- acetate electrophoresis to examine degrees of genetic differentiation among the disjunctive populations. Evidence was obtained to support the recognition of three morphs: two 'good' species (Oreochromis mossambicus and Tilapia mariae) and a third morph that is a potential interspecies hybrid between O. mossambicus and one or more of the related Oreochromis species O. honorum, O. niloticus and O. aureus. Distributions of the three morphs are described, and their likely origins and potential impacts on native fauna are discussed.