No abstract

With the increasing degradation of coral reefs worldwide, interest has grown in the possibility of reef rehabilitation using coral transplantation as a tool (Clark and Edwards 1995). More data are clearly needed on the physiology and ecology of the different scleractinian species that are dominant on reefs, particularly in terms of responses to transplantation. Coral species that would be more desirable or useful as seed material (in the form of introduced fragments or colonies) in the restoration of natural reef populations should obviously be able to survive the trauma associated with breakage and relocation, and to be able to respond similarly to naturally established colonies in a new environment.With these considerations in mind, the aims of this experiment were (1) to elucidate the effects of transplantation to two depths on the skeletal extension rate of two species of scleractinian corals, Porites cylindrica and Porites (Synaraea) rus; and (2) to compare growth of transplants with naturally established colonies. Materials and methodsColonies of Porites cylindrica and Porites (Synaraea) rus were collected from the reef flat off Bolinao (northwestern Philippines) on 23 July 1994. Fragments were broken off using a wire cutter and transported in seawater to the Bolinao Marine Laboratory of the Marine Science Institute. Travel time was 10-15 min. The fragments were held in a shallow outdoor raceway and segregated into species. Thirty fist-sized fragments and 30 finger-sized fragments (nubbins) were prepared for each species. The nubbins were mounted on 50;50;3 mm Plexiglas plates using cyanoacrylate adhesive. The fist-sized fragments were cleaned of epibiota and boring organisms using an electric sander and drill. All specimens were labelled with plastic tags and stained with 10 ppm Alizarin Red S for 24 h (Lamberts 1978).Entire colonies of both species (20-25 cm in diameter) were collected from the same site on the reef flat at 1 m depth and also stained with Alizarin Red S in the laboratory. They were returned to their original location and allowed to grow, as the control treatment, until the end of the experiment.Correspondence to: H.T. Yap Two sites were prepared for transplantation: (1) a sandy area, 10 m deep, beyond the margin of the reef slope (deep treatment); and (2) a subtidal sandy area, 1 m deep, on the reef flat (shallow treatment). Six 1;1 m steel grids were laid horizontally in each site, and were raised 20 cm from the bottom by means of steel rods driven into the substrate.The coral transplants were tied to the grids with plastic-coated copper wire. Specimens belonging to the two species and two size classes were represented in each grid, arranged equidistantly following an interspersed design. The transplants were allowed to grow in the grids for 14 months, and were cleared of fouling organisms every month. Transplants which died during the course of the experiment were collected for measurement, and all surviving transplants were sacrificed in the end. Data on mortality are reported elsewher...