PErfECT “Photogrammetry, gEnetics, Ecology for red coral ConservaTion”

 

PErfECT “Photogrammetry, gEnetic, Ecology for red coral ConseravTion” is a project funded by TOTAL Foundation and executed by the Laboratoire des Sciences de l’Information et des Systèmes (LSIS - UMR 7296 CNRS) from the Aix-Marseille University (France) in collaboration with the Spanish National Agency for Scientific Research (CSIC, Spain). 

The main objective of the project is to develop innovative Tools for the conservation of the Mediterranean red coral, Corallium rubrum

 

Red Coral: model species


Red coral, Corallium rubrum, is an emblematic species from the Mediterranean Sea. The beauty of its bright red calcareous skeleton is famous since ancient times. Red coral is handcrafted into various artifacts ranging from amulet to jewelry that are sold in ethnic to luxury fashion markets. Accordingly, this species is one of the most valuable marine resources on Earth.

Red coral is a longlived species, which can live more than one hundred year. This species is characterized by a low growth rate estimated around 0.25mm per year in diameter. A colony with a diameter of 1 cm is thus more than 60 years old. Corallium rubrum belongs to the coralligenous, one of the most diversified habitats of the Mediterranean Sea. 

The coralligenous is a hot spot of biodiversity in the Mediterranean. Due to their tree-like structure, the red coral colonies increase the spatial complexity of the coralligenous. This structural species is thus characterized by a key ecological role in this habitat and its occurrence directly impacts the development of other species.

Harvesting is the main threat impacting the red coral. Indeed, harvesting pressures lead to a deep shift in the demographic structure of red coral populations with dramatic decreases in population density and a total extinction of large size colonies. Nowadays, natural populations are mainly composed by small size colony (<10 cm high). Nevertheless, colonies higher than 25 cm can be found in Marine Protected Areas. The study of red coral colonies from private collection or from museums demonstrated that this species could reach more than 50 cm in height. The low population dynamic of the red coral (low growth and recruitment rates) is likely the main characteristic explaining the low resilience of harvested populations. Moreover, during the last decades, red coral has been impacted by mass mortality events likely linked to climate change. 

In this context, questions addressing the conservation of the red coral received particular attention from scientific and manager communities. For instance, various national or international conventions were adopted in order to limit the harvesting pressure on the red coral populations. Considering the central ecological role of the red coral within the coralligenous habitats, the conservation of this species should directly beneficiate to the conservation of the coralligenous and more generally to the conservation of Mediterranean biodiversity.