Steps towards the evaluation of coral reef restoration by using small branch fragments

"Gardening" of denuded coral reef habitats is a novel restoration approach in which sexual and asexual recruits are used. The present study aimed at t he evaluation of the potentiality for restoration use of different types of small fragments subcloned from the Red Sea coral species Stylophora pistil lata. In situ short-term (24 h, Ca-45 method) and long-term (1 year, alizar in Red S vital staining) experiments revealed high variation (up to 70%) in growth rates between up-growing branches of a specific genet, and that tip ratios in dichotomous branches (n = 880) differ significantly between newl y formed and older branches. further emphasizing the within-colony genetic background for spatial configuration. Small, isolated branches (< 4 cm) rev ealed high survivorship (up to 90%, 1 year) and up to 20-30% (1 year, singl e- vs. dichotomous-tip branches, respectively) growth, showing that small-s ized branches are suitable for restoration purposes. Results differed signi ficantly between genets. Total length added for dichotomous-tip branches wa s in general at least twice that recorded for single tips of a specific gen et. Restoration protocols may be applied either by sacrificing whole large colonies via pruning high numbers of small fragments or, by pruning only a few small branches from each one of many genets. An in situ "nursery period " of approximately 8 years is predicted for S. pistillata small fragments.