National

Nago base plan threatens dugong habitat

by Mick Corliss

Staff writer

Less playful than dolphins and not as awesomely powerful as whales, dugongs have somehow failed to capture the popular imagination like their more dynamic cetacean brethren. But this endangered creature, found off the east coast of Okinawa’s main island, may soon steal the limelight.

Experts estimate that around 100,000 dugongs exist worldwide, ranging from eastern Africa to Australia. In Japan, they have only been located around Okinawa Island — the northern limit of their habitat.

Most dugongs in Okinawa have been seen along the eastern coast near the Henoko district of Nago in the northern part of the island — the same area where the government plans to relocate the U.S. Marine Corps’ heliport now at the Futenma Air Station in Ginowan.

The plan calls for a joint military-civilian airport. But dugong experts worry that an airport built in the coastal waters the beasts frequent would further imperil their already dwindling numbers.

Compounding the problem is a lack of data on the mammals. Despite information compiled from reports of spottings, such as last April’s sighting of six at the same time, it is not clear how many exist. Information about exactly where they feed, rest and hide is also scarce.

“In Okinawa, almost 100 percent of dugong sightings have been along the east coast. And they are planning to build a military facility right in the middle of this area,” said Taro Hosokawa of the Dugong Network Okinawa citizen’s group.

Sitting amid a clutter of books, papers and dugong models in a dilapidated storehouse-turned-studio on the outskirts of Nago, this Tokyo transplant says that despite a long infatuation with whales and dolphins, it wasn’t until he came to Okinawa that he realized there were dugongs in Japan or that the area where they have been found is earmarked for development.

“I thought dugongs were basically extinct in Japan until I moved here five years ago,” he said.

After hearing that one had become entangled in a net and drowned, Hosokawa decided to go diving off the coast and look for dugong trenches — paths in the seaweed eaten clean by the creatures.

Originally a dolphin and whale enthusiast, the designer of sea mammal replicas and models has since become a dugong devotee, and recently has become a leading advocate for the protection of the creature. A study conducted by Hosokawa’s group found there were 53 dugong sightings between 1998 and 1999, with more than half of them off the Henoko area.

The group is continuing its surveys in the hope of learning more about the number of dugong and their behavior. The group then plans to push a proposal to establish a dugong sanctuary — like that off the Great Barrier Reef in Australia.

In Okinawa, dugong bones have been found among Stone Age remains, indicating they used to exist in greater numbers and in close proximity to people, Hosokawa said. Because they eat seaweed, which can only grow in depths of up to 15 meters, dugongs tend to dwell close to shore, making them easy prey for people.

Faced with a food shortage after World War II, islanders reportedly fended off starvation by ravaging the dugong population. This may be one of the reasons why they seem to avoid people, making them hard to study, according to Hosokawa. In addition to being threatened by the loss of their habitat, dugongs also become tangled in fishing nets and die or get stranded after washing ashore. Six reportedly met this fate in the 1990s.

Now Hosokawa feels it is his duty to alert people to the presence of the creature off the coast of Henoko, and make people realize that a new military facility could adversely effect the local dugong population.

“There are lots of other animals that live in or near the areas occupied (by the U.S. military), and they get attention. But no one speaks for the dugong, so I feel like I have to.”

Hosokawa argued that Japan needs to get its priorities straight and ensure that dugong preservation does not fall prey to politics. Many people have heard of the dugong, but few know much about them, he said. Like humans, dugong can live to an age of 70, and reach maturity after the age of 10.

They can reach 3 meters in length and weigh 400 kg — dwarfing even the biggest sumo wrestler. But because they mature so slowly and have calves only every three to five years, dugong are hard-pressed to maintain their numbers.

The creature, like the manatee of the Atlantic, is probably best known as the mystery behind the mermaid legend. But a long look at the animal’s blunt mug and it is hard to see how a sailor, even a desperately nearsighted one, could mistake it for a beautiful seafaring woman with a tail.

More accurately, the dugong is also known as the sea cow or sea pig. While the dugong may not get the adoration received by some of its sea-going companions, it could certainly use it, Hosokawa said.

“Even people aware of the problem often mistake it for a prefectural issue, but it is more than that. It is a national and an international issue. This creature is facing extinction and I want people to know this,” Hosokawa said.