This study investigated effects of eutrophication and sedimentation on juvenile abundance, juvenile mortality and community structure of scleractinian corals on fringing reefs on the west coast of Barbados, West Indies, in 1989. Juvenile abundance was lower on eutrophic/high-sediment reefs than less eutrophic/low-sediment reefs, but juvenile size was larger on the former. The larger size could result from size-selective mortality against smaller juveniles on the eutrophic reefs, from lower recruitment to the eutrophic reefs, or from faster growth on the eutrophic reefs. Juvenile mortality was higher on the eutrophic reefs than the less eutrophic reefs and may result from increased smothering of corals by algae and sediment. Algae were more abundant on the eutrophic reefs, probably in response to elevated nutrients and/or because grazers (Diadema antillarum; herbivorous fish) were less common on eutrophic reefs. Juvenile community structure on all reefs was dominated by Type 1 corals (high recruitment, high natural mortality), but Type 2 corals (low recruitment, low natural mortality) became more common in adult communities on the less eutrophic reefs. This transition in community structure did not occur on the eutrophic reefs, adult community structure continuing to be dominated by Type 1 corals. The fact that the pattern of relative abundance of species in the juvenile community is maintained in the adult community on the eutrophic reefs suggests that juvenile mortality rates of different species are similar on eutrophic reefs' and hence that differences in adult community structure between eutrophic and less eutrophic reefs may be largely explained by interspecific differences in juvenile mortality becoming smaller on eutrophic reefs.
