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2013-10-24 - Article/Dans un journal avec peer-review - Anglais - 27 page(s)

Delroisse Jérôme , Fourgon Didier, Eeckhaut Igor , "Reproductive cycles and recruitment of the two co-existing tropical brittle-stars from the barrier reef of Toliara (Madagascar), Ophiocoma scolopendrina and Ophiomastix venosa" in Cahiers de Biologie Marine, 54, 4

  • Edition : CNRS - Cahiers de Biologie Marine, Roscoff (France)
  • Codes CREF : Biologie (DI3100), Sciences exactes et naturelles (DI1000)
  • Unités de recherche UMONS : Biologie des Organismes Marins et Biomimétisme (S864)
  • Instituts UMONS : Institut des Biosciences (Biosciences)
  • Centres UMONS : Biosys (BIOSYS)

Abstract(s) :

(Anglais) The reproductive cycles and recruitment of two co-existing ophiuroids species, Ophiocoma scolopendrina and Ophiomastix venosa, were investigated on the barrier reef of Toliara (Madagascar) from February 2000 to April 2001. The two species inhabit the boulder tract of the barrier reef. O. scolopendrina reproduces continuously, has planktotrophic larvae, and new recruits are seen year-round while O. venosa has a clear annual reproductive cycle. In the latter, spawning occurs during the austral summer (from November to February), larvae are lecitotrophic, and new recruits (individuals less than 4mm disk diameter) were seen mostly from February to May. It is hypothesized that differences in reproductive strategies shown by the two species are linked to local environmental conditions and species adaptations. The tolerance to emersion shown by O. scolopendrina allows it to successfully colonize regularly emerged areas. As for O. venosa, while adults live in permanently immersed tidal channels, juveniles were often seen as symbiont of O. scolopendrina, which allows them both to resist emersion and to increase the species recruitment area.