Preliminary study of community development and scleractinian recruitment on fibreglass artificial reef units in the sedimented waters of Singapore

Abstract

1. Fibreglass was used to make specially designed reef enhancement units (REUs) for three reef sites in Singapore. Units were established in areas measuring approximately 20 x 50 m. 2. The units are compact and light enough to be deployed from small boats by scuba divers, and are suitable for shallow reefs with limited visibility. 3. The design of the REUs precludes excessive sediment build-up on the settlement surfaces, while allowing water currents to flow through the system. 4. The REUs were monitored monthly over two years to observe community development and scleractinian coral recruitment on the exterior surfaces. Recruitment was compared between REUs and rubble quadrats at one study site. 5. The REUs were colonized by turf algae within the first month, followed by crustose coralline algae, macroalgae, ascidians and hydroids. At the end of two years, the percentage cover of crustose coralline algae at all three sites was more than 50%. 6. The first incidence of coral recruitment was six months post deployment, and recruitment rates at the end of the monitoring period ranged from 0.10 to 4.75 recruits per square metre for the three sites. Recruits show better survival and growth on REUs compared to rubble areas. 7. The most abundant recruit was Pocillopora damicornis, followed by favids, acroporids and poritids. Copyright © 2006 John Wiley & Sons, Ltd.