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[D-4.2.4 Utilization of Indicator Organisms for Evaluating the Health of Coral Reef Ecosystems]

[Contact Person]

Mitsuhiko Sano
Department of Global Agricultural Sciences,
Graduate School of Agricultural and Life Sciences,
University of Tokyo,
Yayoi, Bunkyo-ku, Tokyo 113, Japan
Tel:+81-3-3812-2111, Fax:+81-3-3812-0529

[Total Budget for FY1995-1996]

5,956,000 Yen (FY1996 2,974,000 Yen)

[Abstract]

　To ascertain whether butterflyfishes(Chaetodontidae) can be utilized as indicators for the health of coral reef ecosystems, relationships between live coral cover and chaetodontid species richness and abundance were investigated by censusing fish from a series of reefs with different proportions of live coral at the Sekisei Lagoon and Iriomote Island, Ryukyu Islands. There were highly positive relationships between live coral cover and mean numbers of fish species and individuals per 10 min observation, probably because many representatives of this fish family are obligative or facultative coral feeders. In addition, the abundance of Chaetodon trifasciatus, which is an obligative coral feeder and the most common chaetodontid species at the study sites, rose with increasing live coral cover. These results suggest that chaetodontid fishes, especially obligative coral feeders, are candidates as indicator organisms for the health of coral reef ecosystems.

[Key Words]

Chaetodon trifasciatus, Chaetodontid fishes, Indicator organisms, Live coral cover, Obligative coral feeders