Abstract:
Globally, coral reefs are declining due to numerous global and local stressors, including increasing prevalence of coral diseases and other lesions. Declines in coral cover related to occurrence of lesions, which can be a symptom of disease, can have major effects on ecosystem function and services. While many coral lesions are more intense on human-impacted reefs, evidence linking some lesions, like multifocal pink spots (MPS) on Porites corals, to human impacts is mixed. Our study explores spatial patterns of MPS on fringing reefs off the north shore of Mo’orea, French Polynesia during 2016 and 2021. We chose sites within bays previously documented as humanimpacted, as well as along the less impacted open coast. We conducted surveys quantifying prevalence, intensity, and within-colony dispersion. During both years, prevalence and intensity of MPS were highest within the bays and decreased in open coastal areas, implying MPS in Mo’orea may be positively associated with anthropogenic impacts. Further, dispersion of MPS within individual colonies in both years was Poisson-distributed, not aggregated. We hypothesize that this dispersion pattern may be related to differences in the two known causative agents’ life cycles and emphasize the importance of more research on identifying causes. Our research provides the first documentation of spatial patterns of MPS for South Pacific islands and demonstrates MPS are more widespread and may have a broader relationship to human impacts than previously known.
