Harem structure and female territoriality in the dwarf hawkfish <Emphasis Type="Italic">Cirrhitichthys falco</Emphasis> (Cirrhitidae)

We investigated the territoriality and the spatial and mating relationships of the haremic hawkfish, Cirrhitichthys falco, on a reef off Kuchierabu-jima Island in southern Japan. Each individual maintained a territorial home range which was defended against same-sex conspecifics at the boundary of the home range. The territory of each male encompassed the territories of 2–3 females, allowing the male to completely monopolize mating opportunities with those females. Based on our observations, we classified the harem type of C. falco as a territorial female type. Large juveniles maintained independent home ranges outside the female territories. In contrast, small juveniles were allowed to cohabit within the territory of an adult female. Stomach contents analysis revealed that the smallest size class of C. falco fed primarily on copepods. In contrast, all other size classes fed primarily on decapods. Together, these results suggest that female territoriality plays an important role in defending food resources.