Once again, there is trouble in paradise. In this case, it is the clear blue sea around Okinawa’s Yaeyama islands, which boast more than 350 coral varieties in some of the world’s most stunning reefs.
Researcher Nobuo Saeki, 58, can literally lay his fingertips at the source of the problem.
During a dive in July in Miyara Bay, at the mouth of the Miyaragawa river on Ishigakijima island, his worst fears were confirmed.
About 500 meters off the coast, 7 to 8 meters down, Saeki found the world-renowned coral reefs covered in a layer of red, clayish soil. Some formations were buried.
When he stirred up the water by hand, the sand clouded up. The coral underneath had turned white, a sign of critical condition or death.
The distinctive red soil comes from farmlands on the Yaeyama islands. It has been eroding for decades and is now causing increasingly severe damage to Okinawan waters, and the thriving tourist industry upon which it feeds.
The soil washes off farms, then rivers take it out to sea. The erosion has increased sharply since 1972, when the United States returned Okinawa to Japanese sovereignty.
After the handover, large-scale farmland reform projects were implemented in essentially the same manner as those on the main islands of Japan. By failing to consider the unique soil and climate characteristics of the Yaeyama islands, the slipshod projects exposed large areas of land to erosion.
Sugar cane was widely planted, mainly on steep slopes because of the lack of flat arable land, leaving the region’s distinctive red soil exposed to heavy rains.
In fiscal 2001, conventional development projects in Okinawa Prefecture led to the washing away of 46,000 tons of red soil, while farms lost as much as 220,000 tons. Many of the reefs are now entirely covered.
Fearful of losing the abundant blessings of the sea, and the consequent negative effects on fishery and tourism, the Okinawa prefectural government finally started to take protective measures in the current fiscal year.
Ishigakijima island, where most of the larger farms are based, accounts for about 90 percent of the population of the Yaeyama islands. It has suffered the worst coral reef damage.
The prefectural government designated a river basin near the east coast of Ishigakijima island as a special model area to prevent soil erosion. The plan is to transform steep land into milder slopes and surround farms with plants that easily take root in the soil. The measures will be tailored to each individual plot.
The prefectural government ultimately aims to cut soil erosion in half by fiscal 2011. But Saeki, who is head of the Yaeyama Environmental Network, a local environmental conservation group, asks, “Are those methods really sufficient to protect coral reefs?”
Over the past five years, he has studied the actual conditions of soil outflow and documented the damage it has caused coral as it piles ever higher on the seabed near the coast.
Based on his findings, he has urged local governments to take more drastic measures to protect the coral.
The Yaeyama reefs cover about 19,000 hectares, accounting for nearly 60 percent of the nation’s total. There are as many as 363 kinds of coral here, making it one of the most varied reef regions in the world.
The red soil deposits are in fact only the latest in a string of threats to this international gem. Since the 1980s, the coral reefs here have been steadily dying. One reason is outbreaks of crown-of-thorns starfish, which eat coral. Another is a rise in water temperature.
Takashi Kobayashi, 50, started raising sugar cane on Ishigakijima island about 18 months ago. A staffer of a Tokyo-based environmental conservation group, Kobayashi has spent a decade working to protect the coral, and he recently decided to live on the island as a farmer.