Size-Dependent Dispersal by Goniopora Stokesi Corals at Semporna, Eastern Sabah, Malaysia

Galaxea, Journal of Coral Reef Studies 13: 9-10（2011）

Photogallery

Size-dependent dispersal by Goniopora stokesi corals at Semporna, eastern Sabah, Malaysia

Bert W. HOEKSEMA1, * and Zarinah WAHEED1, 2

1 Department of Marine Zoology, Netherlands Centre for Biodiversity Naturalis, P.O. Box 9517, 2300 RA Leiden, The Netherlands 2 Borneo Marine Research Institute, Universiti Malaysia Sabah, Jalan UMS, 88400 Kota Kinabalu, Sabah, Malaysia

* Corresponding author: B.W. Hoeksema E-mail: [email protected]

Communicated by Saki Harii (Ecology Editor)

Keywords budding, free-living corals, mobility, polyp balls

Free-living corals of Goniopora stokesi Milne Edwards & Haime, 1851 (Scleractinia: Poritidae) were observed at vari- ous sites during the Semporna Marine Ecological Expedition (SMEE 2010) in eastern Sabah, from 29 November to 18 De- cember 2010. At two out of 63 sites, dense aggrega tions (75- 100% cover) with extended polyps had formed only on the sandy bottom of depressions (at 16-20 m depth). These corals could not leave, unlike scattered G. stokesi corals found on sandy slopes, which may migrate in downward direction (Hoeksema 1988). The largest coral patch (Fig. 1a) was c. 200 m2 (Denawan I.) and the other only c. 40 m2 (Larapan I.). Some colonies showed budding through the formation of polyp balls (Fig. 1b), which is a known trait in this species (Boschma 1923; Rosen and Taylor 1969). A few parent in- dividuals had loose polyp balls around them, which had dropped and rolled to available space nearby. Most large specimens were dome-shaped with their dead, fl attened base on the sand or partly buried inside it (Fig. 1b). Only a few were found in upside-down position or laying on a side (Fig. 1c). The heavy weight and fl at underside of these large corals would likely hinder any further migration and may render them practically immobile. Our observations suggest that free-living G. stokesi corals can disperse easily when they are Fig. 1 Goniopora stokesi at Denawan I. a Field of densely distributed cor- small and may eventually form dense fi elds when they are als, most of which have their tentacles extended. b A large parent colony (located in the centre of Fig 1a) with several budding polyp balls; tentacles physically entrapped by the surrounding reef. are completely or partly retracted. c Turned-over coral exposing its dead, fl at underside. Scale bars: 1 cm 10 Hoeksema and Waheed: Size-dependent dispersal by Goniopora stokesi corals at Semporna, eastern Sabah, Malaysia

Acknowledgments SMEE 2010 was funded through WWF Malaysia. Research permission was granted by Sabah Parks, Department of Fisheries Sabah, and the Economic Planning Unit, Malaysia.

References Boschma H (1923) Über die Bildung der jungen Kolonien von Goniopora stokesi durch ungeschlechtliche Fortpﬂ anzung. Zool Anz 57: 284-286 Hoeksema BW (1988) Mobility of free-living fungiid corals (Scleractinia), a dispersion mechanism and survival strategy in dynamic reef habitats. Proc 6th Int Coral Reef Symp 2: 715-720 Rosen BR, Taylor JD (1969) Reef coral from Aldabra: new mode of reproduction. Science 166: 119-121