Monitoring coral reef macroalgae: Different pictures from different methods

Despite the low coral abundance and high macroalgal abundance on many coral reefs worldwide, coral reef monitoring programs often focus narrowly on hard corals. As part of a benthic monitoring program to assess the effects of no-take marine reserves in the Florida Keys National Marine Sanctuary, we compared two measures of macroalgal abundance: percent cover estimated from video transects and biomass estimated from harvested quadrats. The overall patterns of macroalgal abundance were similar between the two methods, but the species-specific resolution of assemblage structure was much greater in the biomass sampling. Neither method provided adequate estimates of crustose coralline algae nor algal turf abundance. Considering the present emphasis on improving and coordinating coral reef monitoring on both national and global scales, we advocate inclusion and standardization of the estimation and reporting of reef macroalgal abundance.