Prevalencia de enfermedades coralinas y blanqueamiento en 2019 en Akumal, un sistema arrecifal bajo presión antropogénica

Introduction: Globally, coral reefs are undergoing an unprecedented crisis characterized by rapid structural and functional degradation associated with cumulative local pressures and climate change. In the Mexican Caribbean, conservation efforts implemented since the 1990s were associated with a relatively stable trend in reef condition between the mid-1990s and the mid-2010s; however, since 2018, an intensification of disturbances has been observed, marked by disease outbreaks and mass bleaching associated with high mortality rates. Objective: This study characterized the benthic community of the Akumal coral reef system in the Mexican Caribbean and evaluated the prevalence of coral bleaching and diseases under a context of high anthropogenic pressure. Methods: In 2019, high-resolution video-transect surveys were conducted across 37 reef sites in the shallow (10 m) and deep (20 m) fore reef. Univariate and multivariate analyses were used to characterize the benthic community and the prevalence of disease and bleaching in scleractinian corals in both reef zones. Results: We found differences in benthic composition between reef zones, where the shallow fore reef was characterized by the dominance of crustose coralline algae (CCA) and Siderastrea siderea, while the deep fore reef showed greater abundance of macroalgae, coral rubble, sponges, and Porites spp. Total coral cover was low and similar in both zones (≈8%). Across the Akumal reef system, disease prevalence reached 6%, with more than 80% of affected colonies showing signs of Stony Coral Tissue Loss Disease, whereas bleaching prevalence was low (≈2%). Disease prevalence was more frequent in the shallow fore reef, while bleaching predominated in the deep fore reef. Discussion: The high algal dominance, low coral cover, and clear signs of SCTLD impact in Akumal reveal a reef strongly impacted by chronic and recent processes of regional degradation. Although bleaching prevalence in 2019 was low, the simultaneous occurrence of disease and bleaching in some species suggests important stress conditions within the coral assemblage. Conclusion: The observed conditions suggests a highly compromised reef, whose future trajectory will likely be strongly conditioned by the interaction between coral diseases, ocean warming, and local degradation processes.