The rôle of substratum choice and subsequent survival in determining the patterns of recruitment of the colonial ascidian Podoclavella cylindrica (Quoy & Gaimard) (Clavelinidae : Aplousobranchia) were examined. Larval settlement preferences on five substrata were determined by following individual larvae underwater and observing settlement behaviour on their first encounter with a substratum. The survival of settling larvae was monitored daily for 30 consecutive days in quadrats on the five substrata. Larvae settled preferentially on substrata that showed reduced mortality of settlers, hence recruitment was correlated with settlement. In almost all cases larvae rejected the unfouled surfaces of sponges, preferring those with epifauna, and settled in highest densities on bare space. Mortality of new recruits varied markedly between substrata but was very low on bare space. Juvenile mortality resulted from overgrowth by neighbouring invertebrates and from the removal of epifauna, associated with sponges, on which juveniles had settled. © 1987.