Structure démographique et état d'exploitation des populations du corail rouge Corallium rubrum (Linnaeus, 1758) dans le Nord de la Tunisie

Abstract

The Mediterranean red coral (Corallium rubrum) is emblematic species of the Mediterranean Sea. Red coral trade and its use as amulets and in jewellery industry began many millennia ago. C. rubrum have been the target of intensive fishing throughout the Mediterranean, especially at depths shallower than 50m. Our study focuses on the analysis of the demographic structure of C. rubrum at depths ranging from 38 to 118 m in order to evaluate the impact of harvesting. Results showed that for all areas combined, 20% are pristine sites and 10% are devastated. In addition, 51% of colonies diameters are fewer than 7mm (recommendation of minimum legal size, GFCM-SAC). The red coral colonies dwelling shallower than 50 meters in Bizerte and Tabarka/Sidi Mechrig have the lowest basal diameter (6,2 ± 1.6 and 6,57 ± 0,9 mm, respectively). However, the red coral colonies dwelling deeper than 50m including Esquerquis benches have the largest basal diameter with an average of 8,83±3,2 mm. To preserve the red coral fishery in Tunisia, it is necessary to provide a management plan at the regional level, taking into account the specificity of each fishing area. Also a close collaboration between fishermen, scientists and policy makers is needed to establish harvesting regulation and to encourage management at the regional level. Indeed, recovery of this longlived and slow-growing species could be detected only over decades or even centuries.