Metamorphosis in an Amphidromous Goby, Sicyopterus Lagocephalus (Pallas 1767) (Teleostei: Gobioidei: Sicydiinae): a True Metamorphosis?

Abstract

In the tropical Indo-Pacifi c and the Caribbean regions, insular river systems are mainly colonised by diadromous species, including fi sh, which are mainly represented by Gobiidae (Sicydiinae), molluscs and crustaceans. The Gobiidae life cycle is adapted to the conditions in these distinctive habitats, which are young oligotrophic rivers, and subject to extreme1Research Unit BOREA «Biology of Aquatic Organisms and Ecosystems» Muséum national d’Histoire naturelle, CNRS 7208, IRD 207, UPMC, 57 rue Cuvier, cp26, 75231 Paris Cedex 05, France; aE-mail: keith@mnhn.fr bE-mail: taillebois@mnhn.fr 2The University of Tokyo, Atmosphere and Ocean Research Institute, Division of Marine Life Science, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan. 3Research Unit BOREA “Biology of Aquatic Organisms and Ecosystems” Muséum National d’Histoire Naturelle, CNRS 7208, IRD 207, UPMC, 7 rue Cuvier, CP32, 75231 Paris Cedex 05, France. cE-mail: dufour@mnhn.fr dE-mail: rousse@mnhn.fr *Corresponding authorseasonal climatic and hydrological variations (Keith, 2003). These species spawn in freshwater, the free embryos drift downstream to the sea where they undergo a planktonic phase, before returning to the rivers to grow and reproduce, hence they are called amphidromous (McDowall, 1997, 2007). The practical details of their biological cycle and the parameters leading to such extreme evolution in amphidromous gobies are poorly known (Lord and Keith, 2007), despite the fact that these gobies contribute most to the diversity of fi sh communities in the Indo-Pacifi c and the Caribbean insular systems, have the highest levels of endemism (Nelson et al., 1997; Keith and Lord, 2010) and a high economic value as food resource for local populations.