Breathing life in corals

Researchers of the National Institute of Oceanography (NIO) in Goa have artificially repopulated corals in the Lakshadweep islands. Three years ago, the scientists started experimenting to develop a cost effective method to regrow corals. About 60 per cent of them had died in 1998 in the islands. After trying different substrates including natural rocks, the researchers zeroed in on cement slabs. About a hundred fragments of corals were tied down to five cement slabs, which were then placed on iron frames at a height of about 0.5 metres above the seabed. The raised height ensured that sediments did not accumulate on the corals and impede their growth. The coral fragments were sourced from the reef affected in 1998. Coral growth was monitored once a month, except during monsoon. Microalgae growing on the corals were removed since they stunt coral growth. By December 2007, the corals had grown into colonies up to a foot (0.3 metres) in size. The slabs were then moved to the reef and wedged between rocks. They found that the number and diversity of other life forms like fish had increased near the transplanted slabs. However, this was more of a qualitative observation, says M Wafar, the scientist at the NIO heading the project. To begin the repopulating exercise, the researchers used corals, Acropora and Pocillopora species, which can grow up to 20 cm in a year. “We chose fast growing species because the results are more dramatic. We are also growing other species to ensure that reef diversity is enhanced,” Wafar said. He and colleagues chose to grow the corals by asexual budding, as it was cost-effective. Corals also reproduce sexually and can be grown in hatcheries where they breed. But this is a more expensive option. With budding, the researchers just had to provide a suitable location with a good substrate. “Corals can also be induced to grow faster by electrical stimulus but we chose the most cost effective way so that the community could be involved,” Wafar added. Some of the community members were taught scuba diving and shown how the 1998 incident had affected the corals. This was done so that they could realize the importance of corals. The researchers hope to get the community to continue the repopulation work. All the material—cement, iron frames and coral fragments—can be sourced on the islands. The project was funded by the Union Ministry of Environment and Forests and involved the local Lakshadweep administration. Such repopulation and translocation projects have been carried out elsewhere in the world too: Guam in the Western Pacific Ocean in 1979 and more recently in various islands of Hawaii, Micronesia and in a marine national park in Kenya. These efforts have met with mixed success. The results were positive, only in the short term, and the corals died after a few years. “Re-growing corals is not easy. Sedimentation, current patterns and substrate orientation can affect corals. It will take at least another four to five years before the NIO project’s success can be gauged,” says Naveen Namboodiri with the coastal and marine programme at the Ashoka Trust for Research in Ecology and Environment, Bangalore. Ôûá

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