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Coral recovery from the 1998 bleaching event is facilitated in Stegastes (Pisces: Pomacentridae) territories, Okinawa, Japan Accepted: 20 August 2001 / Published online: 19 October 2001 Ó Springer-Verlag 2001 The coral reefs at Sesoko Island (Okinawa, Japan), like many others in the Indo-Paci®c, were severely a€ected by high SST and high irradiance in the summer of 1998; few corals survived. Survival was species speci®c and size dependent. While Acropora colonies >5 cm were among the most heavily a€ected, most colonies less than 5 cm survived (Loya et al. Fig. 1 A Stegastes territory at Sesoko Island, Okinawa, Japan 2001). However, survival after the 1998 bleaching event was dependent on where the coral colonies were growing. On many Okinawan reefs coral recovery is in¯uenced by the presence of Stegastes spp. (Pisces: Pomacentridae). Stegastes spp. are territorial ®shes that feed on epilithic algae which they aggressively defend against herbivory by other ®shes and echinoderms (Lison de Loma et al. 2000). Consequently, epilithic algal mats develop in Stegastes territories (Fig. 1). The most abundant herbivores on Okinawa are urchins, particularly Echinometra mathaei, although densities are lower inside Stegastes territories (e.g., 21.6‹6.3 m±2 E. mathaei outside and 10.5‹5.1 m±2 E. mathaei inside a Stegastes territory). Urchins graze epilithic algae and inadvertently erode the reef carbonate (Hibino and Van Woesik 2000), and may increase mortality of juvenile corals by incidental abrasion when urchin numbers are high (Sammarco 1980). While Acropora recruitment is ubiquitous along the Sesoko Island reef (Van Woesik 2000), the Stegastes territories have facilitated Acropora survival Fig. 2 Acropora spp. mean and 1 SD of the number of colonies at by precluding high incidental herbivorous impact 2 2 di€erent size classes inside (4 ´ 1 m ) and outside (4 ´ 1 m ) a (Fig. 2). In contrast, the depauperate state of the Stegastes spp. territory (sample size n=4) in June 2001; other Caribbean reefs is often blamed on a lack of herbivory territories show similar results (Hughes 1994), as macroalgae are known to inadvertently abrade neighboring coral colonies (River and Edmunds 2001), and recruitment and recovery are higher in Diadema-grazed habitats (Edmunds and Carpenter 2001); yet in Okinawa, Acropora coral communities thrive in the soft, unabrasive epilithic algal mats characteristic of Stegastes territories.

References Edmunds PJ, Carpenter RC (2001) Recovery of Diadema antillarum reduces macroalgal cover and increases abundance of juvenile corals on a Caribbean reef. Proc Natl Acad Sci USA 98(9):5067±5071 Hibino K, Van Woesik R (2000) Spatial di€erences and seasonal changes of net carbonate accumulation on some coral reefs of the Ryukyu Islands, Japan. J Exp Mar Biol Ecol 252(1):1±14 Hughes T (1994) Catastrophes, phase shifts, and large-scale degradation of a Caribbean coral reef. Science 265:1547±1551 Lison de Loma T, Harmelin-Vivien M, Naim O, Fontaine M-F (2000) Algal food processing by Stegastes nigricans, a herbivorous damsel®sh: di€erences between an undisturbed and disturbed coral reef site (La Reunion, Indian Ocean). Oceanol Acta 23:793±804

Reef sites

Coral Reefs (2001) 20: 385±386

Loya Y, Sakai K, Yamazato K, Nakano Y, Sambali H, Van Woesik R (2001) Coral bleaching: the winners and the losers. Ecol Lett 4:122±131 River GF, Edmunds PJ (2001) Mechanisms of interaction between macroalgae and scleractinians on a coral reef in Jamaica. J Exp Mar Biol Ecol 261:159±172 Sammarco PW (1980) Diadema and its relationship to coral spat mortality: grazing, competition, and biological disturbance. J Exp Mar Biol Ecol 45:245±272 Van Woesik R (2000) A metacommunity model predicts coral diversity regulated by post-settlement mortality. Biodiversity Conserv 9(9):1219±1233

M. Suefuji Department of Chemistry, Biology and Marine Science, University of the Ryukyus, Nishihara, Okinawa 903-0123, Japan R. van Woesik (&) Department of Biological Sciences, Florida Tech, 150 West University Boulevard, Melbourne, Florida 32901-6988, USA E-mail: rvw@®t.edu

Reef sites

Coral Reefs (2001) 20: 385±386