The demersal fish assemblages of the infra and circalittoral coastal rocky bottoms of the Aeolian Archipelago (Central Mediterranean Sea) studied by Remotely Operated Vehicle (ROV)

摘要

Demersal fish assemblages on the rocky bottoms of the Aeolian Archipelago were investigated using a Remotely Operated Vehicle (ROV) within the framework of research activities aimed at drawing up the zoning proposal for a new Italian national marine protected area. Visual assessments were conducted around the seven main islands by means of 36 ROV transects. The video material was divided into 3 parts belonging to 3 Archipelago sectors (Western, Central and Eastern) and into 3 depth ranges (20-50, 51-120, 121-190). Thirty taxa of teleosts (29 species and 1 genus) belonging to 16 families were recorded. The assemblages were numerically dominated by some schooling fishes, such as Anthias anthias , Callanthias ruber and Chromis chromis that exhibited a depth-related partitioning of space, and three non-gregarious species, namely Serranus cabrilla , Coris julis and Lappanella fasciata . In terms of species composition, the assemblages observed in the sectors of the Archipelago largely overlapped. No significant sector-related differences were detected in fish species richness, diversity and total density. Species composition and the investigated assemblage parameters were significantly affected by depth. The pattern of variation in species richness among depth ranges differed from one archipelago sector to another. No significant interaction between the depth range and sector factors was observed in terms of species diversity and total density. Diversity values at 20-50 and 121-190 m depth were similar and significantly higher than at 51-120 m depth. Fish total density showed a clear downward trend with increasing depth, although significant differences were detected between the 20-50 and 51-120 depth layers and the deepest one. Overall, the demersal fish assemblage of the Aeolian Archipelago was poorly diversified and depleted, most likely due to overfishing. This information highlights the importance of adopting specific measures aimed at the recovery of overexploited resources and the restoration of entire marine ecosystems.