Genomic diversity of an emblematic and harvested species, the red coral Corallium rubrum : a collaborative effort for its conservation and management

The red coral (Corallium rubrum) is an emblematic species of the Mediterranean Sea and the neighbouring Atlantic Ocean. This long-lived species is impacted by a combination of direct and indirect anthropogenic pressures. Fishing pressures since centuries for jewelry have deeply modified the demographic structure of red coral populations. At the same time, insufficient knowledge of the species' spatial and vertical distribution hinders the implementation of effective management measures against the widespread impacts of other destructive fishing practices. More recently, marine heat waves linked with anthropogenic climate change led to large-scale mass mortality events at low depths (up to 40-50m depths). In this context, the effective management of this species requires considering the evolutionary potential of the populations, and therefore their genetic diversity. In the framework of the research programme on red coral led by the General Fisheries Commission for the Mediterranean (GFCM), in collaboration with an international consortium, we analysed around 600 samples covering a major part of the distribution range of this species from the Atlantic Ocean (Portugal) to the Eastern Mediterranean Sea (Greece), with a focus on harvested populations below 50 m depth. We used Restriction sites Associated DNA sequencing (RAD sequencing), and the recently assembled reference genome, to genotype more than 25,000 Single Nucleotide Polymorphim (SNP) markers on non-model species. The results evidenced the main genetic clusters and the patterns of population diversity of this species. These results allow discussing how genomic data can be used in management and conservation of harvested marine species. Furthemore, these data can also be improved to be used for traceability of red coral commercial trade, and forensic analyses. Note that this abstract is a collaborative work from the experts of the GFCM Research programme on red coral : we didn’t list all of them at submission.