Population genomics in Mediterranean vulnerable ecosystems: the case of the black coral Antipathella subpinnata

Mediterranean seamounts and canyons represent one of the most important and less studied deep vulnerable marine ecosystems (VMEs). Marine forests of the black coral Antipathella subpinnata (Ellis & Solander, 1786) characterize these ecosystems creating complex three-dimensional habitats, hosting a rich associated fauna and attracting numerous species of commercial interest. However, these corals are particularly vulnerable to direct damages (e.g., commercial fishing activities), mostly because of their arborescent morphology and low growth rate. Quantify the level of genetic variability of populations inhabiting different seamounts and their levels of connectivity with deep coastal populations is a crucial step for an effective policymaking and resource management. In fact, populations found on seamounts if are not connected with coastal populations could be more isolated, became smaller and therefore more susceptible to natural and anthropic perturbation. Recently developed techniques allow genome-wide identification of genetic markers for a better understanding of the population structure in species with limited genome information as the case of A. subpinnata. Here, for the first time, using restriction-site associated DNA analysis (2bRAD), we successfully genotyped individuals from one Ligurian seamount, one Tyrrhenian canyon and four deep coastal populations (Liguria and Calabria) to detect current genetic diversity and to identify barriers to gene flow. Data have been integrated with the environmental features and reproductive behaviour of the species to understand their influence on the observed genetic pattern. The genomic approach should be used to implement conservation and management decision and to achieve Good Environmental Status of Mediterranean deep vulnerable marine ecosystem