Ecological health status of black coral reefs (Myriopathes panamensis & Antipathes galapagensis) in the North Pacific of Costa Rica

Black corals are one of the ancient marine organisms in the mesophotic ecosystems, associated with the rocky reefs and barely known in Central America. Belonging to the Antipatharia order, Myriopathes panamensis and Antipathes galapagensis are two of the three known species in the Pacific coast of Costa Rica. These two where recently reported at a depth range of 15-45 meters and taxonomically described in the Gulf of Cuajiniquil, Guanacaste, a place that has a particular ocean condition related to the influence of the Thermal Dome of Costa Rica and lots of fisher communities who use the ecosystem services that these environmental bioengineers offer. In Costa Rica there are a few studies about the black corals, and little is known about the ecological importance of these species in the ecological dynamic. This study aims to assess the associated fauna of black coral reef ecosystems in the Gulf of Santa Elena and Playa Blanca Bay, Guanacaste. It provides a baseline understanding of the complex biological interactions surrounding black coral colonies, serving as valuable input for conserving the ecological integrity of these habitats.
The ecological status and macrofauna associated with various coral colonies were evaluated through SCUBA visual surveys and photography. During the assessment, every colony within a 30-meter transect was measured and examined for the presence of vertebrates and invertebrates utilizing the black coral as shelter or for other purposes. Additionally, the general substrate characteristics of the area were documented using a remotely operated vehicle (ROV) and GoPro footage to capture a comprehensive view of the habitat. Our findings reveal that black corals serve as vital nurseries for reef-associated bony fishes, including families such as Apogonidae, Cirrhitidae, Lutjanidae, and Serranidae. These species frequently rely on coral colonies for refuge and feeding. Among the invertebrate fauna, the most representative groups were Ascidiacea, Mollusca, Ophiuroidea, and Porifera, several of which were consistently associated with both species of black coral observed.
These results highlight the critical ecological role that black corals play in the Gulf of Cuajiniquil and Playa Blanca Bay. To safeguard these ecosystems, it is imperative to expand research efforts to better understand the impacts of fisheries, organism extraction, and climate change on these habitats.