Genetic connectivity patterns of Pocillopora verrucosa in southern African Marine Protected Areas

A coherent management plan for coral reef communities should take into account the patterns of connections among distant reefs in order to prioritise conservation efforts to those areas that are important larval sources. At present, the inclusion of such connectivity assessments into Marine Protected Area (MPA) planning is hindered by the lack of knowledge of the exact patterns of connectivity among reefs. To evaluate such patterns, microsatellite loci were used to assess the population genetic structure of the coral Pocillopora verrucosa in currently established MPAs in South Africa and southern Mozambique. All local collections were sexually reproducing (mean genotypic diversity ratio N-g:N = 0.88) and differed significantly from Hardy-Weinberg equilibrium due to heterozygote deficits, and genetic diversity decreased with increasing latitude. Bayesian analyses (using STRUCTURE) and F-ST analysis (F-ST = 0.054) identified southern Mozambique as a separate cluster from South Africa, suggesting weak connectivity between southern Mozambique and South African reef communities over ecological time scales. However, southern Mozambican reefs may contribute recruits to the South African reefs over many generations via a stepping-stone approach, highlighting that the conservation of reefs operates on scales that are often beyond geographical/political boundaries.