Ōike

What it is

• A karst lake on Minamidaito Island formed by rainwater dissolving limestone.
• The largest natural lake in the Nansei Islands covering 0.47 square kilometers.
• One of Japan's 500 important wetlands with high salt concentration.
• A body of water where levels fluctuate every six hours with the tides.

What to see

• A Bruguiera gymnorhiza mangrove colony on the northern shore.
• A national natural monument designated for its unique mangrove growth.
• Introduced fish species including carp, silver crucian carp, and tilapia.
• A sluice gate used to regulate water for local agricultural use.

Notes written by Japan Gems from facts in Japanese Wikipedia.