The serious overexploitation of red coral (Corallium rubrum) due to illegal harvesting has resulted in the loss of coral habitats and the biodiversity they support. The species is also vulnerable to global climate change and is now considered endangered. In addition, recovery from disturbance can take decades due to C. rubrum's low resilience and slow re-colonisation. Restoration techniques such as the transplantation of coral fragments, branches or even whole colonies have been applied to tropical corals. However, few restoration studies have been conducted on Mediterranean corals, although marble has been identified as a highly suitable substrate for growing corals. The EU-funded 'Mediterranean red coral management and conservation' (CORGARD) project aimed to restore C. rubrum colonies using coral gardening techniques. Researchers also investigated how factors such as population structure, colony size, food availability and competition affect the mortality and growth of transplanted red coral. Red coral larvae that had settled on marble tiles and galvanic electro accreted iron tiles were raised in aquarium tanks and retransplanted after one year. Adult colonies were also collected from the wild and retransplanted in areas where the local population was depleted by illegal harvesting. Transplanted colonies were monitored to determine survival and recruitment rates. Coral fragments seized from illegal harvesters were also transplanted and carefully monitored. The techniques developed by CORGARD were applied to other benthic suspension feeders, including Eunicella species and cold water corals. A long-term study into the effects of ocean acidification was also conducted on C. rubrum. In addition, a socioeconomic study was carried out into the economic value of an alternative to red coral for jewellery making. CORGARD outcomes will help to halt the decline in red coral. The results can be used to predict the outcome of future transplantation, thereby providing methods for restoring devastated red coral populations. The identification of cheaper and more sustainable alternatives will help put an end to the illegal harvesting of red coral and help conserve marine ecosystems.
Red coral, Mediterranean Sea, biodiversity, marine ecosystem, Corallium rubrum, illegal harvesting, coral habitat, climate change, coral gardening, ocean acidification, jewellery making