Survival of hurricane-generated coral fragments and a disturbance model of reef calcification/growth rates

Abstract

Hurricane Gerta, with winds reaching 150 km/h, crossed the Belize barrier reef on September 18, 1978. Breakage and scouring of corals occurred in all zones of the reef to a depth of approximately 25 m. Survivorship of storm-generated coral fragments and detached colonies is strongly size dependent, conforming to the power function Y=4.44X^0.66 where Y is the percent of fragments and X is the fragment size. Forty-six percent of detached Acropora palmata branches, which are larger ( \(\bar X\) =37.6 cm long) than fragments of other species ( \(\bar X\) =16.7 cm long), survived. Overall, 39% of fragments and detached colonies survived. This high survivorship, which probably increased the total number of colonies present, and redistribution of corals may explain the rapid recovery of reefs from all but the severest hurricanes. Storms appear to prevent coral reefs from reaching a mature state characterized by low calcification and growth rates. Therefore, we suggest that long-term reef calcification and growth rates are highest on reefs periodically distrubed by storms of intermediate intensity.