Coral Transplanting: A Technique for Repopulating Devasted Reef Areas

Hudson, J

This report outlines a method used to transplant both hard and soft corals into an area of Molasses Reef in the Key Largo National Marine Sanctuary that was damaged by the August 4, 1984 grounding of the freighter WELLWOOD (Fig. 1). Grounding of the WELLWOOD killed an estimated 90 percent of all hard and soft corals within a 644 m2 area of the impact zone. An additional 638 m2 area of live coral is estimated to have sustained 75 percent mortality either by direct contact with the ship's hull, contact with and/or burial under grounding generated rock debris, or by shading and smothering during the 12 days the ship remained hard aground (Hudson and Diaz, in prep). Still easily identified in aerial photographs taken almost 1 year after the incident, the main damage areas (Fig. 2) remain a virtual roadbed of pulverized coral debris that is gradually being coated with a succession of algal epiphytes (Fig. 3). Smith (1985) monitored recolonization of hard and soft corals over a 5-year period at a ship grounding site on a Bermuda reef. He found that, although there was active recruitment of hard corals into the damaged area, an average of only 25 cm2/m2 per year of coral cover has been generated there by natural means. Surprisingly, he reported that new octocorals (soft corals) have not appeared on the damaged reef despite the fact that they are normally abundant on Bermudan reefs. Dr. Thomas Bright and his associates are presently conducting a study similar to Smith's at the WELLWOOD site. Thus far, they report little evidence of new coral growth in the impact area. As of this writing, this author has observed no new hard corals in the reef framework damage area and little evidence of recolonizing by soft corals. Consequently, in order to test a possible alternative to slow, random recruitment and growth of isolated corals over long time periods, a 16 m^2 test plot of transplanted hard and soft corals was established along one edge of the major impact area (Fig. 2).