Seascape dynamics of a coral disease outbreak in Hawaii

When trying to understand patterns of disease transmission, it is essential to estimate the rate at which individuals become infected. Over the past five years, there have been three coral disease outbreaks of tissue loss diseases in Kaneohe Bay, Oahu, Hawaii resulting in localized mass mortality of the host coral species Montipora capitata. These progressive tissue loss diseases cause coral tissue to disassociate with the coral skeleton, usually resulting in total colony mortality. During the most recent outbreak (winter 2015) we designed a natural experiment to estimate force of infection in the field, and determine whether benthic characteristics of the coral community (size of host, distance from host to infected individuals, coral community composition) increased or decreased the probability of survival. We determined that colony size and distance to infected neighbors were the most important determinants of infection likelihood and calculated a force of infection, which is key to understanding epidemiology in any disease and for modeling potential intervention strategies. We plan to use this information to better understand disease dynamics for tissue loss diseases in coral more broadly and to identify putative vectors of disease transmission.