Recruitment and habitat selection of newly settled Sparisoma viride to reefs with low coral cover

Abstract

Live scleractinian corals are a prime microhabitat for many recruiting coral reef fishes, yet live coral cover has exhibited widespread declines, and the impact of this loss on recruiting fishes is not well understood. Although reduced recruitment rates of parrotfishes (Scaridae) have been observed after loss of coral cover, increased juvenile parrotfish abundance observed in connection with increased macroalgal abundance on reefs suggests that some parrotfish may be capable of utilizing macroalgae as recruitment microhabitat. To test this hypothesis, recruitment rates of newly settled stoplight parrotfish Sparisoma viride were measured on reefs in the upper Florida Keys that have lost much of their coral cover. Although S. viride has previously been shown to strongly associ- ate with the branching coral Porites porites on Caribbean reefs, we found that on reefs with low coral cover, S. viride occurred most frequently in areas of high cover of the macroalgae Dictyota spp. Fur- ther, this microhabitat association scaled up such that reefs with increasing macroalgal cover (up to ~16%) supported greater densities of juvenile S. viride. At higher levels of Dictyota spp. (>16% cover), site-specific S. viride recruitment leveled off, suggesting the influence of other processes such as differential larval supply. These results indicate that newly settled stoplight parrotfish are able to utilize the increased macroalgal cover associated with loss of coral cover and that this microhabitat may provide an alternative recruitment refuge.