Macroalgae reduces survival of nursery‐rearedAcroporacorals in the Florida reef tract

Abstract

Recent declines in coral populations along the Florida reef tract have prompted the establishment of coral restoration programs which raise coral species, such as the threatenedAcropora cervicornis, in nurseries ready for outplanting. Large numbers of nursery‐reared coral colonies have been outplanted along the Florida reef tract in recent years, yet few studies have characterized benthic habitats that are considered optimal for colony survival. In 2016, we surveyed 23A. cervicornisrestoration sites, located at six different reefs in the upper Florida Keys. We examined the condition of the outplanted corals and quantified the benthic assemblages adjacent to the outplanted coral colonies. We found that whereA. cervicornissurvived for more than 1 year, the substrate significantly supported less brown macroalgae of the genusDictyotathan at sites whereA. cervicornishad died. Coral survival was highest at sites with less than 15%Dictyotacover. These results suggest that the habitat conditions that supportedDictyotaspp. were not conducive toA. cervicornisgrowth and survival. Restoration practitioners should avoid attaching nursery‐raised corals to substrate withDictyotaspp. cover greater than 15%.