The government earmarked 152 million yen Friday to survey and protect dugongs off Okinawa and assess the effects of the planned construction of a civilian-military airport there.

The Environment Ministry will receive 115 million yen to investigate dugong habitats, the sea-grass beds on which they feed, and the animal's genetic relationship to relatives in such countries as Australia and the Philippines.

The ministry plans to launch the survey around the end of February, according to ministry officials.

The Agriculture, Forestry, Fisheries Ministry will spend the rest of the money devising ways to prevent fishermen from mistakenly catching the endangered sea mammals in fixed nets and to consider how to foster algae distribution.

The money will be allocated from the government's 10 billion yen Okinawa development budget for the current fiscal year. The government has allotted the same sum for the purpose annually since fiscal 1999.

The plans come in the runup to a planned revision of a special law to promote Okinawa Prefecture's economy.

Environment Minister Yoiko Kawaguchi said Friday the revision would also place new emphasis on the environment, promoting the preservation of Okinawa's environment rather than just preventing pollution.

"Furthermore, it will task the ministry with promoting ecotourism," she said.

The ministry has been preparing for the research since several dugongs were spotted by the Defense Facilities Administration Agency off Nago in Okinawa during a preliminary survey in October 2000.

Japan is considering building the offshore airport near Nago in a bid to relocate the heliport operations of the U.S. Marine Corps Futenma Air Station in Ginowan, central Okinawa Island. The airport is being considered for joint military-civilian use.

The sea around Okinawa is the only dugong habitat in Japan and one of the northernmost locations where the creatures can be found.

Conservationists fear the planned military facility will be constructed in the very area where dugongs are most often found. It is unknown how many dugongs there are in the waters off Okinawa.

Dugongs have fishlike bodies and square-shaped snouts. They range in length from 2.2 meters to 3.4 meters and can weigh as much as 400 kg. They can live for 70 years. Dugong sightings are believed to have given rise to myths about mermaids and sirens.