E. Trip, K. Clements, D. Raubenheimer, J. Choat
Journal of Fish Biology, 78, pp. 741-761, (2011)
Butterfish, Functional protogyny, Gonad development, Labridae, Sexual maturation.
The sexual ontogeny of butterfish Odax pullus was examined in
the Hauraki Gulf of New Zealand through histological analysis of gonad
material, size and age information and seasonal patterns of sexual
maturation. The patterns of gonad development and schedules of male
recruitment were established and sexual ontogeny of O. pullus
was diagnosed as monandric protogyny, with all males developing from
mature females after female-to-male sex reversal. All individuals
underwent an immature female phase before maturing as functional females
at 228·7–264·8 mm fork length (LF) and at 1·1–1·5
years of age, and there was no evidence of a juvenile bisexual phase.
Degenerating mature oogenic elements were found in the gonad lumen of
individuals with developing spermatogenic tissue, providing histological
evidence for functional protogyny. Sex change was estimated to occur at
359–379 mm LF and 2–3 years of age. The diagnosis of monandric protogyny for O. pullus
coincided with the pattern of sexual ontogeny seen in the majority of
labrids, particularly those of the same clade (tribe Hypsigenyini) and
contrasted with that seen in a number of other temperate labrids. This
study suggests that the protogynous mode of sexual development in O. pullus is likely to be lineage-specific, i.e.
associated with the phylogeny of labrid sexual development, and is not
constrained by environmental effects on the evolution of sex change in