An outbreak of sea cucumbers hinders coral recruitment
An outbreak of a small sessile sea cucumber, Ocnus sanya, occurred on the degraded Luhuitou coral reef in Sanya Bay, Hainan, China. This study explored the pattern of distribution of O. sanya on the reef and the impacts of the high abundance of O. sanya on post-settlement mortality of Pocillopora damicornis recruits. The density of O. sanya ranged from about 500 to over 2000 individuals m−2 with 10.95–23.69% cover on hard substrate. Terracotta tiles with O. sanya on the surface accumulated 19.7% more surface sediment than those without sea cucumbers. Post-settlement P. damicornis recruits had significantly higher mortality on terracotta tiles with O. sanya than those without O. sanya after 21 d. Overall, O. sanya appears to increase sediment stress and inhibit coral recruitment, exacerbating the degradation of Luhuitou Reef. This study raises the possibility that such novel outbreak species could contribute significant additional stress on coral reefs at larger scales.
KeywordsSea cucumber outbreak Ocnus sanya Pocillopora damicornis Coral recruitment Luhuitou Reef China Coral reef degradation
This study was funded by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA13020201), the National Nature Science Foundation of China (41676150 and 31370499), Science and Technology Service Network Initiative (KFJ-EW-STS-123), Science and technology Planning Project of Guangdong Province, China (2014B030301064). L. J. McCook was supported by a President’s International Visiting Expert Professorial Fellowship from the Chinese Academy of Sciences (2016VEA025). We are grateful to reviewers for their valuable and constructive comments that vastly improved the manuscript. On behalf of all authors, the corresponding author states that there is no conflict of interest.
- Arévalo R, Pinedo S, Ballesteros E (2007) Changes in the composition and structure of Mediterranean rocky-shore communities following a gradient of nutrient enrichment: descriptive study and test of proposed methods to assess water quality regarding macroalgae. Mar Pollut Bull 55:104–113CrossRefPubMedGoogle Scholar
- Birrell CL, McCook LJ, Willis BL, Diaz-Pulido GA (2008) Effects of benthic algae on the replenishment of corals and the implications for the resilience of coral reefs. Oceanogr Mar Biol Annu Rev 46:25–63Google Scholar
- Huang H, Li XB, Yang JH, Lian JS, Huang LM (2009) An outbreak of the colonial sand tube worm, Phragmatopoma sp. threatens the survival of scleractinian corals. Zoological Studies 48:106Google Scholar
- Li XB (2011) Identification of major factors influencing the composition, spatial and temporal variation of scleractinian coral community in Sanya, China. Ph.D. thesis, Chinese Academy of SciencesGoogle Scholar
- McCook LJ, Folke C, Hughes T, Nyström M, Obura D, Salm R (2007) Ecological resilience, climate change and the Great Barrier Reef. In: Johnson JE, Marshall PA (eds) Climate change and the Great Barrier Reef, a vulnerability assessment. Great Barrier Reef Marine Park Authority and Australian Greenhouse Office, Australia, pp 75–96Google Scholar
- Zhao MX, Yu KF, Zhang QM, Qi S (2009) Evolution and its environmental significance of coral diversity on Luhuitou fringing reef, Sanya. Marine Environmental Science 28:125–130Google Scholar