Early onset of zooplanktivory in equatorial reef coral recruits

Abstract

Scleractinian coral recruits face multiple challenges as theyattempt to meet the metabolic demands for growth anddevelopment post-settlement. Although coral recruits ofsome scleractinian species can obtain zooxanthellae fromtheir parent colonies to enable autotrophy (Richmond 1997),the development of tentacles is essential for the capture ofparticulate matter to supplement the nutrient and energysupply of the growing juvenile coral. However, studiesexamining the onset of zooplanktivory in coral recruits arelimited (Cumbo et al. 2012).In April 2011, gravid colonies of the broadcasting coralAcropora hyacinthus were harvested from the reef off KusuIsland, Singapore (1°13′25′′N, 103°51′38′′E) for ex situspawning and establishment of larval culture (following Tohet al. 2012). The larvae were settled on tiles (2.3 cm×2.3 cm)and the recruits were tagged to determine their age. Using astereomicroscope (Nikon) with a camera setup (Canon), weobservedthat2-day-oldA.hyacinthusazooxanthellaterecruits(n=7) immobilized live 1-day-old Artemia salina naupliiwithin seconds of contact with their tentacles (Fig. 1a). The