Genetic and demographic variation in new recruits of Naso unicornis

Demographic data showed that larvae of Naso unicornis colonizing the reefs of Moorea, French Polynesia, on the same night within a restricted area originated from several spawning events that occurred 67 to 94 days previously. Based on the demographic structure of larvae of N. unicornis colonizing the reef, it cannot be entirely dismissed that siblings colonize together because five spawning dates grouped c . 55% of the captured larvae. Relatedness analysis reinforced these observations and also confirmed that larvae colonizing together were not all siblings. Larvae of the same spawning dates, however, appeared related in some age-classes (72, 74 and 77 days old), suggesting that siblings recruited together. In addition, the larvae appeared genetically different from adults ( P =0·002) and juveniles ( P <0·001) while juveniles and adults were similar ( P =0·100). The variations in allelic and genotypic frequencies in the larvae probably reflect a family-structure that is diluted once larvae are recruited into the lagoon because of high mortality and active movement of fish.