Basic coral distribution data for long term monitoring at Sekisei Lagoon

Sekisei Lagoon is the largest coral sea in Japan that is located at 124°E, 24°20´N. It is 25×20 km in size. This area was selected as a bioindicator of local and global environmental changes. As a first step, the width of live coral around the whole area was surveyed using two techniques. They were 50-m lengths minute diving survey and cruising survey for long line. 135 diving surveys and 45 cruising surveys were carried out successfully over whole Sekisei Lagoon between February 1996 and November 1997. This lagoon suffered global scale coral bleaching on June to August 1998. After the bleaching, periodical monitoring of coral distribution was started at 10 cruising survey lines and 26 diving survey sites. Also, water quality, number of zooplankton, chlorophyll, etc. were measured around the whole lagoon. From the data obtained by cruising survey before the bleaching, coral cover database was made. Also, coral coverage rate and tentative coral map at Sekisei Lagoon are examined from the database