Multispecific, synchronous coral spawning in Singapore

Multispecific, synchronous coral spawning in Singapore Accepted: 10 May 2002 / Published online: 16 October 2002
Springer-Verlag 2002 There are very few reports of multispecific, synchronous coral spawning from low-latitude reefs (e.g. Baird et al. 2001), and it has been suggested that the ‘mass spawning’ phenomenon may be absent or significantly reduced close to the equator (Oliver et al. 1988). Singapore is a small, industrialised and heavily populated island, located approximately 1 north of the equator.

Fig. 1 a A broken branch of Acropora intermedia clearly revealing brightly coloured, mature eggs prior to the spawning event. b A Platygyra verweyi colony releasing egg sperm bundles at night

Reef sites

Coral Reefs (2002) 21: 422–423

Despite there being high levels of sedimentation and turbidity in the coastal waters, reasonably diverse coral communities can be found around some of the islands to the south of the mainland. Sampling of Acropora species to determine their reproductive state was conducted at the southern-most reef off Singapore (Raffles Lighthouse, 110¢N, 10345¢E), on 21 March 2002 (8 days before the full moon). From 22 different Acropora species, 15 (68%) had at least one colony with mature eggs, 48.5% of colonies had mature eggs (pigmented) (Fig. 1a), 10% had immature eggs (unpigmented), and the remaining 41.5% had no visible eggs (n=113). On the 3rd, 4th and 5th nights after the full moon between 8 and 10 p.m. we observed synchronous spawning of corals. At least 18 different coral species from ten genera and five families (Acroporidae, Faviidae, Merulinidae, Oculinidae and Pectiniidae) were observed releasing gametes over the three nights (Fig. 1b). This report documents multispecific spawning of corals in Singapore for the first time and demonstrates that this remarkable phenomenon can indeed be a characteristic of equatorial coral reefs. References Baird AH, Saddler C, Pitt M (2001) Synchronous spawning of Acropora in the Solomon Islands. Coral Reefs 19:286 Oliver JK, Babcock RC, Harrison PL, Willis BL (1988) Geographic extent of mass coral spawning: clues to ultimate causal factors. Proc 6th Int Coral Reef Symp 2:803–810

J.R. Guest (&) Æ L.M. Chou Department of Biological Sciences, National University of Singapore, Blk S2, 14 Science Drive 4, 117543 Singapore E-mail: scip9051nus.edu.sg Tel.: +65 6874 6867 Fax: +65 6779 2486 A.H. Baird Laboratory of Cell and Functional Biology, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa, 903–0123 Japan B.P.L. Goh Natural Sciences, National Institute of Education/NTU, 1 Nanyang Walk, 637616 Singapore

Reef sites

Coral Reefs (2002) 21: 422–423