The brooding cycle of Abatus cordatus (Echinodermata: Spatangoida) at Kerguelen Islands

Abstract

The Schizasteridae includes a high proportion of brooding species. The brooding cycle of Abatus cordatus (a species endemic to Kerguelen) at an intertidal site in the “Golfe du Morbihan” is annual and lasts 8.5 months, from the end of March until the beginning of December. This cycle is reproducible among years. It is synchronous inside the Golfe between two intertidal sites. A displacement of about six months occurs at a deeper site (-50 m). The delay of the cycle and depth does not seem to be related because an open-sea intertidal site has a similar displacement of the brooding cycle. It depends on the gonadal cycle which itself depends on the availability of trophic resources. On this basis and samples taken in January annual brooding cycles are hypothetized to occur in 3 Antarctic species of Schizasteridae from Terre-Adelie in relation to the annual sea ice cover and restricted summer period of primary production.