MEPS 198:121-130 (2000)  -  doi:10.3354/meps198121

Stability of reef fish assemblages: responses to coral recovery after catastrophic predation by Acanthaster planci

Mitsuhiko Sano*

Department of Global Agricultural Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan

ABSTRACT: A long-term monitoring study was conducted at Iriomote Island (Ryukyu Islands, Japan) to explore the responses of a disturbed adult fish assemblage to the recovery of coral on a large reef degraded by an outbreak of the coral-feeding starfish Acanthaster planci. In 1987, 5 yr after the outbreak, I censused a reef in which all of the arborescent corals had been broken apart and the reef formation changed into a flat plain of unstructured rubble. Species richness and numerical density of fishes on the dead reef had decreased severely. Natural recovery of the dead reef was initiated mainly by larval recruitment of branching Acropora corals in 1989. Since that time, fish species richness and density on the recovering reef have increased steadily with the increasing percentage cover of live corals. In 1995 to 1997, when the reef had almost 100% live coral cover, most fish assemblage properties (e.g., species numbers and abundances of the collective assemblage and component ecological groups) on the reef did not differ significantly from those on a nearby reef consisting mostly of arborescent Acropora, which had not suffered A. planci predation. The similarity index indicated about 90% resemblance in species composition of the fish assemblages on the recovered and undisturbed reefs. These results demonstrate that the structure of the disturbed fish assemblage had returned to its pre-perturbation state on the near-completion of coral recovery.

KEY WORDS: Coral reef degradation · Fish assemblage · Recovery · Stability · Acanthaster planci

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