Reproductive behavior and social organization of some Pacific hawkfishes (Cirrhitidae)

Abstract

Ten species of Pacific hawkfishes occur in small social groups consisting of a single male and one or more females. Facultative monogamy occurred regularly in two obligate coral dwelling species while the remaining species were largely haremic. Males had larger body sizes than females within groups but not necessarily between groups. Males defended territories in which females had home areas. Females defended courtship sites within a male's territory against neighboring females of the same social group.Courtship was paired and sequential within groups, commencing just prior to or after sunset and concluding at dusk. Spawning, when observed, was pelagic.•\ 439•\ 魚 類 学 雑 誌Japan.

Sexual pattern ofNeocirrhites armatus (Cirrhitidae) with notes on other hawkish species

“…The two species are apparently similar, both to each other and to other cirrhitids examined, in the derivation of testicular tissue from the junctions of lamellar and alamellar regions at the gonadal walls. Reproductive behaviour and social organization of Cirrhitichthys aureus was also similar to other cirrhitids (Donaldson 1990) in that reproductive groups were male-dominated and sexually dimorphic, with male body sizes greater than those of females within groups (Tanaka & Suzuki 1991, Y. Yogo personal communication).…”

“…A diagnosis of protogyny in Neocirrhites arrnatus represents the first confirmation of this sexual pattern in the cirrhitids. That protogyny might occur in a number of additional cirrhitid species is also suggested by observations of behavioural roles during courtship between larger males and smaller females within distinct single-male/multiple female social groups of various cirrhitid species (Donaldson 1990). These include sequential movement of the largest individuals among smaller individuals within a coral head or between adjacent coral heads, during sunset courtship periods, accompanied by displays suggestive of male courtship behaviour.…”

“…This mating system is hypothesized to provide a reproductive advantage to males when large and to females when small and hence benefit individuals that start life as a female and then change sex to a male (Ghiselin 1969, Warner 1984. Second, protogyny in this group is also suggested by sexual dimorphism in body size (Thresher 1984, Donaldson 1990), a characteristic often, although not exclusively, found in protogynous species (Sadovy & Shapiro 1987).…”

“…The first is a pronounced difference in habitat utilization; Neocirrhites arrnatus is highly site-restricted and occurs only in isolated coral heads, principally Pocillopora eydouxi and P. eleguns. Movement between corals is limited to closely adjacent heads (Donaldson 1990). Adult Cirrhitichthys aureus, on the other hand, are not highly siterestricted.…”

“…All species examined to date exhibit similarities in behaviour and social structure, and many species are sexually dimorphic. Social groups are comprised of pairs, or of a single male and varying numbers of females (Donaldson 1986b(Donaldson , 1990, which can be replaced by facultative monogamy in some obligate coral-dwelling species (Donaldson 1989). Pairspawning occurs sequentially in groups at around sunset (Thresher 1984, Donaldson 1986b, 1987, 1990, Donaldson & Colin 1989, Tanaka & Ohyama 1991, Tanaka & Suzuki 1991.…”