Size Structure and Spatial Distribution of the Corals Mussismilia Hispida And Siderastrea Stellata (Scleractinia) at Armação Dos Búzios, Brazil

Few studies have described the population structure or spatial distribution of corals on Brazilian rocky shores. We present the first quantitative study of populations of two corals at eleven sites at Armação dos Búzios by investigating the size structure and spatial distribution of Mussismilia hispida (Verrill, 1902) and Siderastrea stellata Verril, 1868. Their percentage cover and density were estimated and colony size was measured using a size index based on colony arc, length, and width. Both species occurred in the same depth intervals and showed similar patterns with depth. Siderastrea stellata was usually more abundant than M. hispida and showed site-specific patterns. The colony size structure of both species was generally skewed to the right. One site, Tartaruga R, stood out because of the large size of the corals and the fact that S. stellata colonies fused, forming a continuous carbonate structure. Although rocky shores are expected to have lower abundance of corals than coral reefs, one species (S. stellata), a reef building coral endemic to Brazil, was extremely abundant on Búzios' rocky shores. Armação dos Búzios was considered an ecologically important site for coral growth in Brazil.