・田中幸記 *2 ・平岡雅規

Tatsukusi Bay is at the tip of Ashizuri Cape to face Tosa bay, warm waters, southern Japan. There are many rich coral communities on the coast, and the area is specified in the national marine park. Rich seaweed beds are seen surrounding of coral communities, where seaweed communities were poor. Sea grass and seaweed specimens collected at six monitoring points of biological survey on the coast of Tatsukushi Bay, in February and May in 2005. The environment of St. 1, St. 2, St. 4 and St. 5 are the shore reef zone where many coral communities are. St. 3 is located at the back of the bay, and their seaweeds were the coverage in high density. St. 6 is sandy bottom in the center part, and the wave action were weak in the bay. A total of 85 species included Halophila ovalis of sea grass were identified. The list is comprised with 19 Chlorophycea, 21 Phaeophycea and 44 Rhodophycea. There are many kind the tropical and warm water species, Valonia aegagropila, Dictyosphaeria cavernosa, Caulerpa and Codium in the Chlorophycea. The rich seaweed beds were being made with Sargassum species, S. duplicatum and S. alternato-pinnatum growing in tropical waters