The flathead grey, Mugil cephalus (Linnaeus 1758), is the largest mullet species of the family Mugilidae. The species forms an economically important fishery and aquaculture species throughout its range. It is a euryhaline species which is found in pelagic regions near shores, lagoons, estuaries, lower courses of rivers and freshwater. Information of genetic diversity plays an important role in making informed decisions for scientific management of any fish species. In current investigation, intraspecific genetic variability was examined in M. cephalus individuals (n=263) collected from total six major locations of east and west coasts of India.
Sequence analysis of mitochondrial gene Cytochrome b (1141bp) revealed 64 distinct haplotypes. The mean nucleotide composition of sequences was A (24.9%), T (29.0%), C (31.5%) and G (14.6%). The results displayed high level of haplotype (0.676-0.852) and low nucleotide diversity (0.0011 to 0.0012). Partitioning of genetic variance (AMOVA) revealed significant genetic differentiation among locations. The among group variance was 16.41% while the within population 76.9%. The coefficient of genetic differentiation (0.2310; P<0.05) and levels of gene flow indicated that the population is sub-structured with moderate to high level of genetic variability between populations. The current findings have implications in the fishery management and stock conservation of this species across its natural habitat.