Mesophotic coral ecosystems of Cuba

This paper reviews the current knowledge regarding Cuba’s mesophotic coral ecosystems (MCEs). The first studies of MCEs in Cuba were conducted by Kühlmann in 1964 and Zlatarski and Martínez Estalella in the 1970s. In 2017 a joint Cuba-U.S. expedition was conducted to characterize the MCEs along the entire coastline of Cuba using remotely operated vehicle surveys. A total of 477 taxa of benthic macrobiota and 151 species of fish were identified, and 343 specimens of benthic invertebrates and algae were collected to verify taxonomy and assess population genetic structure. The primary geomorphological features are the deep island slope (125- >150 m), deep fore-reef escarpment (the ‘wall’, 50-125 m), and deep fore-reef slope (30-50 m). Most vertical surfaces of the wall have dense cover of sponges, algae, octocorals, and black corals. Cuban mesophotic corals appeared quite healthy as compared to many shallow Caribbean reef sites; only 0.53% (mainly Agaricia spp.) showed signs of bleaching, and just 0.09% displayed signs of disease/morbidity. Percent cover of the bottom was dominated by algae (23.45%) and sponges (20.41%). Sites outside of marine protected areas generally had lower fish abundances, a possible indicator of historical overfishing. Lionfish were observed at most sites but abundances were low compared to other Caribbean regions. Cuba’s MCEs encompass the entire Cuban archipelago, representing a vast and ecologically important resource that may play an important role in regional coral reef connectivity and persistence across the Gulf of Mexico and wider Caribbean.