Abstract
Reproductive behavior of the wrasse, Halichoeres marginatus, was studied on a shallow reef at Kuchierabu-jima Island, southern Japan. Individuals foraged solitarily at a low density. The population consisted of protogynous hermaphrodites and a few (4.9%) primary males. The species is sexually dichromatic: secondary males showed the terminal phase (TP), and primary males the initial phase (IP) similar to females. In late afternoon large TP males migrated offshore to set up temporary mating territories at the prominent dead coral or rocky outcrops on the slope. They pair-spawned with single females, which migrated there. Non-territorial TP males and IP males intruded repeatedly into the mating territories which were located near the shore. They spawned by streaking, sneaking, and group spawning with females in those territories. The reproductive behavior is compared with that of other wrasses.
