Coastal Area 15101 Adjacent waters of Iriomotejima and Ishigakijima Islands

Basic Information References

Reason(s) for selection Criteria

Characteristics References

These waters include Iriomotejima Island, Ishigakijima Island, and the Sekisei Reef. Coral reefs have formed in the vicinity of Ishigakijima Island, and numerous mangrove forests and tidal mud flats can be found in the river mouth areas and bays. Coral species are highly diverse in the coral reefs off the coast of the Hirakubo Peninsula on northern Ishigakijima Island, the coast from Cape Ugan to Ishizaki, and the Shiraho coast. Mangrove forests of Kandelia obovata, black mangrove, and Rhizophora mucronata unfold at sites including the mouths of the Kara River in the northwest and the Fukido River in the central west of the island, Nagura Bay, Miyara Bay, and the mouth of the Miyara River. Grey mangrove, Lumnitzera racemosa, and Sonneratia alba also grow in Nagura Bay. These mangrove forests are populated by highly diverse creatures, unique in terms of their mangrove species, sizes, origins, bird species, fish species, and other species, with highly divers species of crustaceans and benthic animals as well. The river mouth areas and mangrove forests are home to large numbers of species and populations of snipe and plover. In Miyara Bay and the area of the Miyara River mouth at least 1% of the minimum estimated population of lesser sand plover and at least 0.25% of the minimum estimated population of Pacific golden plover, Kentish plover, ruddy turnstone, and grey-tailed tattler have been recorded. At Shiraho at least 1% of the minimum estimated population of lesser sand plover and at least 0.25% of the minimum estimated population of Pacific golden plover, Kentish plover, ruddy turnstone, and grey-tailed tattler have been recorded. Kabira Bay and the coast of the sea extending in front of Yonabaru have highly diverse deep bay environments, with seaweed beds where Sargassum fulvellum and Gelidiella acerosa grow as well as fringing reefs with high degrees of diversity of species. Nagura Bay also is home to a community of Acetabularia ryukyuensis. In addition, seagrass and seaweed beds also have formed here, where Enhalus acoroides grow (Ministry of the Environment, 2001). The Sekisei Reef is Japan's leading coral habitat. It is important as a source of larvae and is both in a highly natural state and highly diverse (Ministry of the Environment, 2001). Mangrove forests form at the mouths of rivers flowing into the waters in the vicinity of Iriomotejima Island. Kandelia obovata, black mangrove, Rhizophora mucronata, grey mangrove, Lumnitzera racemosa, Sonneratia alba, and other species grow at the Nakama, Shiira, Aira, and Maira rivers, Yubu Island and its tidal mud flats, from Cape Kuba to Cape Akaya on Kohama Island, in Funaura Bay, at the Urauchi River, at the Ayanda, Udara, and Kuira rivers in the southwest. These spots also are highly diverse in benthic animals endemic to mangrove wetlands. Funaura is the northern limit to distribution of mangrove palm. The sandy beaches on the southern coast of Iriomotejima Island (Takahama, Wakarehama) see the highest density of green turtles spawning of any sandy beaches in the Nansei Islands, and the seaweed beds deep in the bays are green turtle feeding grounds. Sakiyama Bay in the western waters, a place that remains in a highly natural state and lacks roads and settlements, is home to expansive pure communities of Enhalus acoroides, with a high diversity of coral species. Amitori Bay also is home to expansive Thalassia hemprichii, Cymodocea serrulata, and Enhalus acoroides communities, with a high degree of diversity of coral species including rare species (Ministry of the Environment, 2001).