Haplotype and meristic variations of oreochromis niloticus and its hybrids present in selected reservoirs in Sri Lanka.

Abstract

The Nile tilapia, Oreochromis niloticus was introduced from Africa’s to Sri Lanka in the 1970s. Since then tilapia has dominated in most of the reservoir fisheries in Sri Lanka. The genetic and meristic variation of the domesticated tilapia was studied using polymorphisms in mitochondrial DNA (mt-DNA) and by analysis of morphometric and meristic characters. Ninety seven fish from three locations, namely Kurunegala, Anuradhapura, Polonnaruwa and ten control samples from the brood stock of the Udawalwe Tilapia Breeding Centre were collected. The genetic analysis targeted 16Sr region of mitochondrial genome. The Meristic analysis included fourteen meristiccounts, which were subjected to discriminant analysis and cluster analysis. The PCR- SSCP procedure of the mtDNA resolved eight haplotypes that overlapped between the four locations. The meristic and the genetic composition were common within the three domesticated fish populations collected from Kurunegala, Anuradhapura, Polonnaruwa and the brood stock of the Udawalwe Tilapia Breeding Centre. The results of this study will significantly contribute towards new inferences regarding management of the brood stocks and the wild stocks of tilapia aquaculture.