Colonization of Juveniles of the Damselfish Dascyllus reticulatus (Richardson) on the Southern Coast of Taiwan

On the southern coast of Taiwan, the majority of juveniles of the damselfish Dascyllus reticulatus (Richardson) live exclusively on table corals on reefs. Patterns of juvenile settlement were evaluated monthly on 5 coral heads from February 1997 to September 1998, to study the influence of recruitment on colonization. The population size, which was negatively linked to rainfall, ranged from 13 (minimal, in August 1997) to 187 individuals (maximal, in September 1998). New recruits occurred throughout the year. There was concordance among the monthly numbers of new recruits in different colonies. The main recruitment season occurred from late summer to early autumn and peaked in October 1997 and August 1998. The old residents had no effects on recruitment. Immigration to colonies was evident in certain colonies. Overall, results suggest that colonization was mainly governed by the influx of juveniles during peak recruitment. Apart from other post-settlement processes yet to be elucidated, migration and environmental factors such as typhoons and rainfall might also have contributed to temporal variations.