Seasonal Transboundary Movement Of Cape Hake (Merluccius Capensis) Across The Western Coast Of Southern Africa

ABSTRACT

This study was conducted to investigate the patterns of genetic differentiation of Cape hake (Merluccius capensis) across Southern Africa, using eight nuclear microsatellite markers to understand the seasonal movements of the two previously identified stocks. The aim of the project was to assess the position of the genetic break in two different temporal sampling events: summer months (February – March) and winter months (June – August) and to investigate the level of genetic diversity for 2017. Individual fishes were chosen randomly from a pool of samples, covering the distribution from the Cunene River Mouth, in northern Namibia, to Cape Town in South Africa. Six main sampling sites were chosen based on latitude and their relative position regarding known oceanographic breaks: Northern Namibia, Central Namibia, Southern Namibia, Orange River, Central West Coast and Southern West Coast. Total genomic DNA was extracted using a standard chlorophorm: isopropanol method of Backeljau, Dewachter &Winnepenninckx (1993). The Polymerase Chain Reaction (PCR) amplification of a fragment of the Control Region (CR) of the mtDNA was done for species validation. A total of 533 individuals were screened for genetic variation at eight nuclear microsatellite loci. The results shows an overall Fixation index (FST ) = 0.160 for summer and FST = 0.112 for winter, which were statistically significant different from zero (p