Restoring reefs with doomed corals

20 Oct 2014. Juvenile corals growing naturally on unstable substrates are useful for stocking coral nurseries to assist reef rehabilitation and restoration.

Loose pieces of reef rubble on which juveniles of Pectinia paeonia and Pachyseris speciosa two common but relatively understudied coral species in Singapore – had naturally recruited were secured and reared in a coral nursery just off Pulau Semakau. Known as ‘corals of opportunity’, their chance of survival is reduced as the rubble pieces toss about in strong currents. Both species on secured rubble demonstrated high overall survivorship and the larger juveniles grew faster than the smaller ones. Prof CHOU Loke Ming from the Department of Biological Sciences in NUS has demonstrated the feasibility of such an approach to support reef rehabilitation efforts in areas affected by high sedimentation and unconsolidated substrate.

With more than 60% of the world’s reefs threatened and impacted by human activities, it is highly relevant to explore different techniques and formulate strategies to assist in their rehabilitation. Juvenile corals on loose rubble which will ultimately perish are an excellent source for reef restoration and this diminishes the need to harvest fragments from healthy colonies for coral transplantation. The added advantage is that naturally recruited juvenile corals ensure the maintenance of genetic diversity. The current findings complement and supplement the growing body of work on coral reef rehabilitation techniques.

CHOULM

Juvenile corals growing on loose rubble pieces (left) and ‘corals of opportunity’ on a rubble piece secured to a coral nursery frame (right). (Image credits: Jani TANZIL, Angie SEOW)

Reference

Ng CSL, Chou LM. “Rearing juvenile ‘corals of opportunity’ in in situ nurseries – A reef rehabilitation approach for sediment-impacted environments” Marine Biology Research. 10(8) (2014) 833.