Outwith: Divers do transplants to turn tide on dying coral reef

Each disc carried a tiny sliver of hope for the reef, in the shape of fingertip-sized sprigs of brightly coloured, fledgling coral.

This undersea work site may look like a scene from a Jules Verne novel, but it is part of a government-led effort to save Japan's largest coral reef, near the southern end of the Okinawa chain of islands. True to form in Japan, the project involves new technology, painstaking attention to detail and a generous dose of taxpayer money.

The project has drawn national attention, coming after alarming reports in the last decade that up to 90% of the coral that surrounds many of Okinawa's islands has died off. This raised a rare preservationist outcry in a heavily industrialised nation whose coastal vistas tend toward concrete sea walls and oil refineries.

The result has been what marine biologists call one of the largest coral restoration projects in the world, begun four years ago. The goal, say biologists, is to perfect methods that could be used around the world to rescue reefs endangered by overfishing, pollution and global warming.

"We have been replanting forests for 4,000 years, but we are only just now learning how to revive a coral reef," said Mineo Okamoto, a marine biologist at Tokyo University of Marine Science and Technology, who has led development of the palm-size ceramic discs. "We finally have the technology."

Critics, however, say the project may be a wasted effort. They say transplanting is futile without addressing the problems that caused the reefs to deteriorate in the first place, like coastal redevelopment and chemical run-off from terrestrial agriculture. There is also the bigger problem of rising ocean water temperatures, for which there may be no easy fix.

Since 2005, the project has planted 13,000 pieces of coral, at a cost of $2m, said Hajime Hirosawa, a preservation officer at the Environment Ministry who helps oversee the transplanting. He admits this is a far cry from the tens of millions of pieces that need to be transplanted in this reef alone, which stretches over an area of about 100 square miles.

Worse, survival rates have been low, Hirosawa said. Only a third of the coral sprigs transplanted in 2005 have survived threats ranging from predators including the crown-of-thorns starfish and 'bleaching', an ultimately fatal condition caused when rising water temperatures turn coral a sickly white.

"Saving the reef is not something that we can do in three to four years," Hirosawa said. "It will take more like 30 to 40 years."

While the project's main goal is environmental, there are also geopolitical motivations. Tokyo is planning a much larger and more expensive coral transplantation to try to strengthen the reef protecting Okinotori, a tiny, remote islet that Japan uses to claim economic control of a vast area of the Pacific Ocean.

The government wants to prevent a strong typhoon from wiping away the tiny outcropping, and with it the basis for Japan's territorial claims, which have already been challenged by China.

There is also a friendly race among global scientists trying to develop the best coral transplantation method. Competing ideas range from creating coral habitat with large concrete 'reef balls' to the use of mild electric current to speed up coral growth.

"This is absolutely worth doing," said one of the team's divers, Ryo Isobe, who works as a diving instructor during the summer tourist season. "When I think of how colourful these reefs used to be, I know we need to do all we can."