Stable coral rubble was used as natural substrata (Fig. 2c) for
all four study sites with depths of 3e8 m: Zona de Restauración
(n ¼ 20), Cueva del Muerto (n ¼ 19), Amarradero (n ¼ 12), Plataforma
Pavonas (n ¼ 21). Only at Zona de Restauración artificial
underwater structures were installed because fragments were
available in sufficient numbers for restoration. Artificial concrete
structures (modules of 60 cm2) (n ¼ 10) had w12 steel-stacks
each and were stabilized at 3e4 m depth (Fig. 2a). In both substrates
each fragment was identified, measured and tagged. Coral
growth progress was measured monthly (cm mo1) during one
year; using calipers (0.05 mm precision) noted maximum apical
height growth distance measured from bottom to top of the