PATTERNS OF CORAL RECRUITMENT AND POSTSETTLEMENT MORTALITY ON BERMUDAS REEFS - COMPARISONS TO CARIBBEAN AND PACIFIC REEFS

The recruitment of juvenile corals and post-settlement mortality are important processes for coral population dynamics and reef community ecology. I monitored juvenile coral recruitment and survival on a severely disturbed reef in Bermuda from 1981 to 1989 and on adjacent healthy reefs from 1986 to 1990. Porites astreoides was the dominant recruiting species at all sites, due to the release of brooded planulae that may settle rapidly. The dominant corals on Bermuda's reef, Diploria spp., were poor recruiters, perhaps due to the broadcast mode of reproduction of these species. However, Diploria spp. have lower juvenile mortality rates compared to P. astreoides, which may explain their abundance on Bermuda's reefs. Brooding corals, primarily agariciids, were the dominant recruits on Atlantic reefs compared to high recruitment rates by spawning acroporids in the Pacific, which may be the result of different environmental conditions and/or evolutionary trends in the two oceans. The latter group also suffered high post-settlement mortality compared to brooding corals in both the Atlantic and the Pacific. Massive corals in both oceans had generally low recruitment rates, related to their spawning mode of reproduction, and low rates of post-settlement mortality. The dominant role of long-lived massive corals on the Atlantic and Pacific reefs can be understood in terms of their life-history strategy in comparison to the relatively short-lived Pacific acroporids and Atlantic agariciids that rely on different strategies to maintain their populations.