Regrowing affected population made easy

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 re-grow 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.