Microsatellites as Genetic Markers for Identification of Exotic Cichlids and Their Hybrids in Sri Lanka — A Preliminary Study
M. P. K. S. K. DE SILVA, N. BAKER and P.B. MATHER
The reservoir fishery in Sri Lanka depends mainly on exotic tilapias, especially on two species, Oreochromis mossambicus and 0. niloticus. These species are known to hybridize readily and uncontrolled hybridization in some reservoirs in Sri Lanka has resulted in adverse effects on stock performance and compromised the fishery in some places. This study therefore, was designed to trial microsatellites as genetic markers for determining the relative purity of different reservoir stocks and for assessing the relative bias of hybrid stocks towards O. niloticus or O. mossambicus alleles. If variation at microsatellite loci can be used to characterize the hybrid status of stocks and relate it with external morphological characteristics, then the markers can be used to evaluate relative stock performance in different reservoirs to determine if the differences in performance are related to genotype (bias towards 0. mossambicus or 0. niloticus alleles) or differences in local environmental conditions.