Location-Specific Metrics for Rapidly Estimating the Abundance and Condition of the Threatened Coral Acropora cervicornis

We developed a method for quantifying the abundance of the threatened staghorn coral (Acropora cervicornis) and evaluated the accuracy of commonly used methods to assess colony condition. For small- to medium-sized colonies, we show that colony ellipsoid volume estimated from simple colony dimensions serves as a reliable and efficient proxy for the more time-consuming, conventional measure of colony total linear extension, and that this predictive relationship varies significantly among extant populations in the Caribbean. We also determined that visual estimates of colony partial mortality closely approximate to true values for colonies with <25% mortality, with in situ estimates outperforming estimates from digital images. These results provide coral reef managers and restoration practitioners with guidance for assessing partial mortality and location-specific regression models to estimate amount of staghorn coral in both extant and restored staghorn populations in Belize, the United States Virgin Islands, and the Dry Tortugas National Park, Florida, U.S.A. As staghorn coral monitoring and restoration efforts continue to expand in the Caribbean, these methods for quickly determining staghorn abundance and condition will directly aid resource managers tasked with monitoring wild populations and tracking restoration success over time.