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

Abstract

ABSTRACT1. 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 Â 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.

Coral Reef Restoration in Singapore — Past, Present and Future

“…The installation of bulky concrete and tyre AR structures required the use of barges, and was deemed expensive and potentially destructive if operated in shallow areas where the structures are recommended to be sited. Dome-shaped fibreglass modules ('Reef Enhancement Units', or REUs), light enough to be transported and stabilized at exact locations by SCUBA divers, were thus fabricated (Loh et al, 2006). The perforated and steep sloping surfaces of each REU reduced sediment accumulation and facilitated water movement through the structure.…”

Simulating the transport of broadcast coral larvae among the Southern Islands of Singapore

“…Miller & Mundy 2003, Tay et al 2011 owing to required planktonic development time in the water column, data from this period were not used. Five existing reefs, where coral larval settlement and recruitment studies have been conducted previously (Loh et al 2006, Tanzil et al 2008, were selected as potential larval recruitment sites for the purpose of this study: Raffles Lighthouse, Kusu Island, Pulau Hantu, St John's Island (1°13' 09'' N, 103°50' 56'' E) and the Sisters' Islands (1°12' 53'' N, 103°50' 02'' E). Potential settlement sites were categorized into 3 zones -the southwestern (I.…”

Fouling assemblages associated with estuarine artificial reefs in new South Wales, Australia

“…The ability of filamentous turfing algae (FTA) to trap sediments however, enables them to thrive in environments with high sediment loads (CONNELL, 2003. Furthermore, FTA is commonly the most abundant taxon and a major contributor to primary production on newly deployed artificial structures (BAILEY-BROCK, 1989;COPERTINO et al, 2006;LOH;. Our results are in agreement with those of previous descriptive and experimental studies that document the dominance of FTA in subtidal areas subjected to high rates of sedimentation (AIROLDI, 1998;IRVING;GORGULA;CONNELL, 2004;BALATA;PIAZZI et al, 2005).…”

“…Artificial reefs designed for fishery enhancement are typically deployed on bottom types of low heterogeneity in order to increase production in otherwise barren areas (WHITE, 1990;LUKENS et al, 1997). The transport and settlement of epibiotic species is a result of passive propagule transport and active larval site selection with flow rates determining to a large extent how far these propagules and larvae will travel (DENNY, 1985;BUTLER, 1991;JUDGE;CRAIG, 1997;HURD, 2000;ENGLAND et al, 2008).…”