Home > Ryukyu Islands > Aguni Island
Aguni Island is located approximately 75 km west of Okinawa Island and is a relatively small island with an area of about 7.6 km² and a coastline of 12.8 km. It lies roughly midway between Okinawa Island and Kume Island. On nearby Tonaki Island, located just to the south of Aguni, coral reef communities differ markedly from those of the Kerama Islands to the east and Kume Island to the west (see the section on Tonaki Island). Does Aguni Island exhibit a similar pattern? To address this question, a survey was conducted on August 18, 2025. Sampling was carried out at five. Sites 1–3 were located along the eastern coast of the island, Site 4 was within the southern reef flat lagoon, and Site 5 was at the southwestern tip of the island.
| Point Number | Point Name | Latitude/Longitude | Dominant Genus | Percentage |
|---|---|---|---|---|
| 1 | Unzaki_east | 26.573939, 127.243632 | Anacropora (トゲミドリイシ属) / Montipora (コモンサンゴ属) | 64.69 % |
| 2 | Uuguhama_east | 26.585339, 127.254496 | Goniastrea (コカメノコキクメイシ属) / Merulina (サザナミサンゴ属) | 39.49 % |
| 3 | Agunigyoko_east | 26.597634, 127.247816 | Pocillopora (ハナヤサイサンゴ属) | 17.39 % |
| 4 | Doudera_north | 26.598103, 127.223549 | Anacropora (トゲミドリイシ属) / Montipora (コモンサンゴ属) | 22.46 % |
| 5 | Fudensaki_south | 26.57271, 127.210271 | Anacropora (トゲミドリイシ属) / Montipora (コモンサンゴ属) | 35.32 % |
The dominant coral genus, inferred from eDNA, was remarkably similar at all five sites. As observed on Tonaki Island, the reefs of Aguni Island were characterized by a relatively low dominance of Acropora, whereas Montipora, Goniastrea, Cyphastrea, and Porites were the dominant genera. In other words, coral reefs of Aguni Island appear to differ from those of Kume Island and Okinawa Island, and instead exhibit a coral generic composition more similar to that of Tonaki Island.
トゲミドリイシ属
(
Anacropora
)
/
コモンサンゴ属
(
Montipora
)
コカメノコキクメイシ属
(
Goniastrea
)
/
サザナミサンゴ属
(
Merulina
)
ハナヤサイサンゴ属
(
Pocillopora
)