Full length articleGenetic structure and consequences of stock exploitation of Chrysoblephus puniceus, a commercially important sparid in the South West Indian Ocean

The slinger, Chrysoblephus puniceus, a seabream of the family Sparidae, is an important commercial linefish species in South Africa and Mozambique. Despites its fisheries importance little is known about the population structure of the species and it is currently managed separately by both countries. The genetic connectivity between localities throughout C. puniceus' core distributional range was investigated using the mitochondrial control region and ten microsatellite loci. The majority of pairwise population comparisons were not significant (P > 0.05) and none remained significant after Bonferroni corrections. While one AMOVA grouping using mtDNA found weak levels of structure separating Gaza and Inhaca in southern Mozambique from other localities, all other groupings for both data sets found no significant among group variation. Similarly, SAMOVA, Mantel tests (P > 0.05) and STRUCTURE analysis using-ln likelihoods were unable to identify genetic structuring through C. puniceus' distribution. MIGRATE-n analysis showed asymmetrical migration between sites with net migration probably influenced by the prevailing oceanographic feature. The results of the study failed to reject panmixia suggesting a single C. puniceus stock. The transboundary nature of a single stock coupled with the uneven temporal and spatial distribution of historical fishing effort likely made the species resilient to exploitation. This raises concerns as current management strategies are not aligned and the species is now harvested throughout most of its core distribution excluding the Ponta do Ouro, Maputaland, St Lucia marine protected areas.