LIFE-HISTORY CHARACTERISTICS OF A CORAL-REEF SPONGE

Study of the life history characteristics of the common Red Sea sponge Mycale fistulifera (Poecilosclerida: Demospongiae) reveals several tr aits which may categorize it as an opportunistic species: (1) at least part of the population is reproductively active throughout the year, providing a continuous supply of larvae for settlement; (2) sponges ma y produce and release a large number (152+/-39 larvae d(-1)) of broode d larvae; (3) released larvae are capable of fast settlement and metam orphosis (minutes to 30 hours post-release); (4) the turnover of the p opulation is high and population size varies with time. From 48 initia l sponges plus 94 recruits, only 25 remained alive after 14 months of observation; (5) most members of the population (> 70%) have a small b ody size (< 30 cm(2)); (6) sexual maturity may occur at an early age. These traits facilitate continuous establishment of M. fistulifera in new spaces on the reef; (7) M. fistulifera, preferred substrate is ano ther opportunistic species, the coral Stylophora pistillata which it o vergrows.