Dependence of Caribbean reef fishes on mangroves and seagrass beds as nursery habitats: a comparison of fish faunas between bays with and without mangroves/seagrass beds

Mangroves and seagrass beds are considered important nursery habitats for c oral reef fish species in the Caribbean, but it is not known to what degree the fish depend on these habitats. The fish fauna of 11 different inland b ays of the Caribbean island of Curacao were compared; the bays contain 4 di fferent habitat types: seagrass beds in bays containing mangroves, seagrass beds in bays lacking mangroves, mud flats in bays containing mangroves and seagrass beds, and mud flats in bays completely lacking mangroves and seag rass beds. Principal component analysis showed a high similarity of fish fa una among bays belonging to each of the 4 habitat types, despite some diffe rences in habitat variables and human influence between bays. Juveniles of nursery species-fish species using mangroves and seagrass beds as juvenile nurseries before taking up residence on reefs-showed highest abundance and species richness on the seagrass beds, and on the mud flats near mangroves and seagrass beds, but were almost absent from bays containing only mud fla ts. The high abundance and species richness on the mud flats near nursery h abitats can be explained by fishes migrating from the adjacent mangroves/se agrass beds to the mud flats. Seagrass beds near to mangroves showed a high er richness of nursery species than did seagrass beds alone, suggesting an interaction with the mangroves resulting in an enhancement of species richn ess. Comparison of fish densities from the 4 different habitat types indica tes that for the nursery species the degree of dependence on a combination of mangroves and seagrass beds as nurseries for juvenile fish is high for O cyurus chrysurus and Scarus iserti, the dependence on seagrass beds is high for Haemulon parrai, H, sciurus, Lutjanus apodus, L, griseus, Sparisoma ch rysopterum and Sphyraena barracuda, and the dependence on mud flats near ma ngroves/seagrass beds is high for L. analis. The dependence on mangroves an d/or seagrass beds is low for Chaetodon capistratus, Gerres cinereus, H, fl avolineatum and L. mahogoni, which can also use alternative nursery habitat s.