Early sex change: A possible mating strategy ofCentropyge angelfishes (Pisces: Pomacanthidae)

Although the presence of socially controlled sex change in pomacanthid fishes of the genusCentropyge has been known since 1978, it has always been assumed that such sex change occurred only after the death or disappearance of the dominant male in single male social groups. Between 1978 and 1983, we observed several incidences of sex change by ranking female angelfishes within their harems and in the presence of the dominant male in each such harem. This phenomenon was observed inCetropyge interruptus andCentropyge tibicen, and occurred frequently enough to suggest the possibility of early sex change as a normal reproductive strategy in these species. Possible advantages of early sex change are discussed.