The Land, Infrastructure and Transport Ministry has come up with ambitious designs for future seaports, including plans featuring floating cities and "weatherproof ports," ministry officials said.

The ministry has already begun to test whether the planned ports, which also include ecologically friendly ports, can be put into practical use by 2050.

The ministry will also start developing equipment that can quickly offload cargo and an automatic traffic control system for ships, the officials said.

Ports featuring floating cities would be connected to metropolitan areas by water buses operating on rivers. Such a system is expected to ease rush-hour congestion on trains.

The weatherproof ports will use a system that absorbs tidal energy at the seabed under the entrance of the bay to prevent high waves from entering the bay, thus providing a safe harbor.

The ports would also have emergency breakwaters that automatically rise from the seabed to block out tidal waves.

The eco-friendly ports are expected to transmit sunlight underwater via optical fibers and improve the water for sea life by pumping in fresh air.

Sea crimes down

The number of cases of crimes committed on the high seas sent to prosecutors in 2000 totaled 6,391, down 17 percent from the previous year and the lowest level since 1996, according to a report recently released by the Japan Coast Guard.

The figure for 1999 was 7,729, said coast guard officials, who attributed the decrease to such factors as the decline in unlicensed seamen and smuggling of humans.

However, the report also records a steady flow of cases involving gun and drug smuggling, with 105 guns and about 490 kg of amphetamines confiscated in 2000.

It adds that cases of illegal dumping, such as abandoned boats, still exceeded 100, with the latest count at 135.