Supporting fisheries management with genomic tools: a case study of kingklip (Genypterus capensis) off southern Africa

Kingklip, Genypterus capensis, is a valuable fish resource in southern
African waters, with a wide geographic distribution spanning
South Africa and Namibia. Previous studies have provided evidence for
multiple stocks in South Africa, but the extent of stock structuring
across the Southern African region remains unclear. In this study, we
genotyped over 40 000 SNPs to characterise the spatial distribution of
genomic variation for G. capensis throughout its core distribution.
Results suggest that fish sampled at the northernmost range (off central
Namibia) are characterised by lower genomic diversity, although the region
exhibited the highest number of private SNPs, suggesting some degree of
geographic isolation. Using neutral and putative outlier loci
independently, we show that kingklip exhibits three population clusters,
“northern Benguela”, “southern Benguela” and South African “South Coast”.
Population differentiation was observed only using “outlier” loci,
suggesting that local adaptation might be one of the main drivers of the
observed differentiation. Overall, our research provides novel insights
into the regional dynamics that can support the sustainable long-term
exploitation of this valuable fisheries resource.