Environmental Biology of Fishes

, Volume 46, Issue 3, pp 281-288

First online:

Both-ways sex change in monogamous coral gobies, Gobiodon spp.

  • Yasuhiro NakashimaAffiliated withDepartment of Zoology, Faculty of Science, Kyoto University
  • , Tetsuo KuwamuraAffiliated withBiological Laboratory, Faculty of Liberal Arts, Chukyo University
  • , Yutaka YogoAffiliated withShowa Women's High School

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access


We confirmed both-ways sex change in the coral-dwelling gobies Gobiodon micropus, G. oculolineatus, G. quinquestrigatus and G. rivulatus rivulatus by mate-removal experiment in the field and by the aquarium experiment of keeping two consexual fish in a coral. Eight species of Gobiodon were found in Acropora corals on the reef flat of Sesoko Island, Okinawa, southern Japan. The 4 species mentioned above bred in monogamous pairs composed of a male and a female matched by size, and the male took care of eggs deposited on the coral branch. In G. quinquestrigatus and G. rivulatus rivulatus males were larger than females in newly formed pairs, and females grew faster than their mates until breeding. The growth-rate advantage in females seems to be the major factor in the evolution of female to male sex change. The gobies strongly depended on host corals, but they moved between the corals after mate loss or coral death to form new pairs. This provides opportunities for the evolution of male to female sex change; the ability to change sex in both directions reduces the frequency of risky movement between host corals to form new pairs. These conditions are very similar to those reported in the both-ways sex change of another coral-dwelling goby Paragobiodon echinocephalus.

Key words

Hermaphroditism Protandry Protogyny Growth-rate advantage Inter-group movement Monogamy Parental care Gobiidae