Preliminary Assessment of Macrobenthos Associated with Red Coral Corallium rubrum (Linnaeus, 1758) Populations in the Northeastern Ionian Sea

The taxonomic composition, structure, and distribution patterns of the macrobenthos associated with Corallium rubrum were studied along the coast of Taranto (Ionian Sea), together with the main features of their red coral population. Underwater video transects were performed by professional divers at three sites in correspondence with coralligenous formations at depths from 50 to 65 m. The results revealed a patchy distribution of red coral, with colonies predominantly located in cavities on sub-vertical cliffs and large boulders. Biometric analysis indicated that young colonies predominated at all sites, while older colonies were lacking, likely because of illegal harvesting. The lower density values were recorded at S1, while S2 and S3 presented higher values. A total of 76 taxa were recorded. S1, the shallowest site, showed a prevalence of calcareous algae, while S2 and S3 showed a greater abundance of filter-feeding invertebrates (Porifera and Cnidaria) with the highest presence of Porifera at S3. The results emphasize the heterogeneity of the macrobenthos together with the high vulnerability of the red coral population, highlighting the necessity of site-specific conservation strategies to contribute to the conservation and management of benthic ecosystems in the northern Ionian Sea.