Resumen de Mangroves and fringing reefs as nursery habitats for the endangered Caribbean sea star Oreaster reticulatus
Robert E. Scheibling, Anna Metaxas
Distribution, abundance and demographic composition of populations of Oreaster reticulatus (Linnaeus, 1758) were sampled in mangrove, fringing reef, seagrass, and sand habitats at sand cayes off the southern coast of Belize. Density and biomass were 1.7-18.3 ind 100 m-2 and 0.9-5.5 kg 100 m-2 among six sites. Dispersion was random, except at a fringing reef where sea stars were aggregated at our sampling scale (15 m2). Mean individual size (radius, R) ranged from 9.7 to 13.7 cm among sites. Populations in mangrove and reef habitats were mainly juveniles (R < 12 cm: 83% and 91% respectively), with characteristic cryptic coloration. Juveniles occurred primarily along mangrove banks and were closely associated with coral colonies in fringing reefs. The proportion of juveniles also was high on a sand flat (54%), although juvenile color morphs were not observed there. Most sea stars had their stomach everted on sediments or detrital matter, but sponge and ascidian prey also were consumed in a mangrove habitat. Mangrove and fringing reefs, like dense seagrass beds, may provide a protective environment for recruits that undergo an ontogenic shift to adult habitats, such as sand flats, as they mature reproductively. Our findings are comparable with previous studies of O. reticulatus in Panama and suggest that levels of recruitment in Central America may be higher than in other parts of the Caribbean.
