NAGO, Okinawa Pref. -- For decades, residents of Henoko Ward in the eastern part of this city have dined on such delicacies as shrimp, crab, turban shells and other shellfish from nearby coastal waters.

They have also fished off and thrown beach parties on Hirashima Island, a mere 600 meters off the U.S. Marine Corps' Camp Schwab. This may all come to an end if the central government decides to build a sea-based heliport here to replace the marines' Futenma Air Station in Ginowan in central Okinawa. That site is to be returned to Japan in the next five to seven years.

Nago Mayor Tetsuya Higa, in a blunt reversal, announced in mid-April that the city will accept Tokyo's proposal to conduct a costly preliminary study for the offshore project. Late last week, the central government started a feasibility study off Camp Schwab, in which four government-assigned firms are to conduct research on local marine life, airspace and sea lanes for local traffic, and take aerial photographs by the end of June.