Distribution and Abundance of Sea Urchins in Singapore Reefs and Their Potential Ecological Impacts on Macroalgae and Coral Communities

다국어 초록 (Multilingual Abstract)

The sea urchin Diadema setosum is often encountered in the coral reefs in the Southern Islands of Singapore. While sea urchins have been known to play a role in regulating algal communities and influencing coral recruitment in other parts of the world, their role in Singapore reefs has not been determined. This study was conducted to determine the distribution and abundance of sea urchins in Singapore reefs, to examine algal cover, algal biomass, algal species and live coral cover, and to determine any interactions between urchin density and algal communities that may impact coral cover. Several reefs in Singapore were surveyed using belt transects measuring 20 m by 2 m, laid down on the reef crest. Abundance of urchins, algal species, biomass, and live coral cover were determined by the use of quadrats within each belt transect. This study revealed an increasing abundance of the sea urchin Diadema setosum in reefs progressing southwards away from mainland Singapore with low density of urchins occurring in Sisters’ Island, St John’s Island, Pulau Tekukor, and Kusu Island, and the highest density observed at Raffles Lighthouse. A significant negative linear relationship between algal cover and live coral cover (P < 0.05) was established. The results of this study indicate that sea urchins may not be an important component of the herbivore guild in Singapore.

참고문헌 (Reference)

1 Perrig M, "The use of photo ID as a tool for estimating population sizes of two Siganid species in Singapore" National Institute of Education, 2008

2 Sprung, J, "The reef aquarium: a comprehensive guide to the identification and care of tropical marine invertebrates" Ricordea Publication 546-, 1997

3 Lim GSY, "The fish fauna around proposed reef sites in Singapore" 333-336, 1991

4 Lim GSY, "The echinoderm fauna of sediment stressed reefs in Singapore" 2 : 245-250, 1988

5 Villalobos FB, "Temporal variation of the sea urchin Diadema mexicanum population density at Bahias de Huatulco, Western Mexico" 56 (56): 255-263, 2008

6 English S, "Survey methods for tropical marine resources" ASEAN-Australia Marine Science Project: living coastal resources, Australian Institute of Marine Science 368-, 1994

7 Newman MJH, "Structure of Caribbean coral reef communities across a large gradient of fish biomass" 9 : 1216-1227, 2006

8 Littler DS, "South Pacific reef plants: a divers' guide to the plant life of South Pacific coral reefs" Offshore Graphics Inc 2003

9 Paul VJ, "Seaweed susceptibility to herbivory: chemical morphological correlates" 33 : 255-264, 1986

10 Knowlton N, "Sea urchin recovery from mass mortality: new hope for Caribbean coral reefs?" 98 (98): 4822-4824, 2001

11 Edmunds PJ, "Recovery of Diadema antillarum reduces macroalgae cover and increases abundance of juvenile corals on Caribbean reef" 98 (98): 5067-5073, 2001

12 Ruiz-Ramos DV, "Population status of the long spined urchin Diadema antillarum in Puerto Rico 20 years after a mass mortality event" 87 (87): 113-127, 2011

13 Low JKY, "Pomacentrid population dynamics on Singapore coral reefs" 44 (44): 53-66, 1997

14 Solandt JL, "Macroalgal feeding characteristics of the sea urchin Diadema antillarum Philippi at Discovery bay, Jamaica" 37 (37): 227-238, 2001

15 Williams ID, "Large-scale associations between macroalgal cover and grazer biomass on mid-depth reefs in the Caribbean" 19 : 358-366, 2000

16 Shanula JP, "Grazing preferences of Diadema setosum and Heliocidaris erythrogramma (Echinoderms) on an assortment of marine algae" 25 : 91-95, 1986

17 Miller RJ, "Evidence for positive density-dependent effects in recovering Diadema antillarum populations" 349 : 215-222, 2007

18 Grignard JC, "Distribution and abundance of the echinoid Diadema setosum (Echinodermata) on sediment stressed coral reefs in Singapore" 13 : 123-132, 1996

19 Sammarco PW(1980)Diadema, "Diadema and its relationship to coral spat mortality: grazing, competition, and biological disturbance" 45 : 245-272, 1980

20 Herrera-Escalante T, "Bioerosion caused by the sea urchin Diadema mexicanum (Echinodermata: Echinoidea) at Bahías de Huatulco, Western Mexico" 53 (53): 263-273, 2005