Contribution à la biologie de la reproduction de trois espèces de "concombres de mer" (Holothuria tubulosa, H. poli et H. sanctori) de la côte ouest algérienne (Ain Franine).

Abstract

Our work is a contribution to the study of the reproductive biology of three aspidochirotid holothurians [Holothuria (Holothuria) tubulosa, Holothuria (Roweothuria) poli et Holothuria (Platyperona) sanctori] that belong to the group of Echinoderms and which have great commercial value. Our survey is based on an annual provided sample and compiled monthly (from July 2016 to May 2017) in the site of Ain-Franin (Oran). The macroscopic and morphometric characteristics of the gonads, the maturity stages as well as the monthly survey of the mean values of Gonadosomatic index (mGSI) have been established. The obtained results on the evolution of the mGSI and the morphometric characteristics of the gonads of the three species show three major phases in the gonadal development: the Gonad maturation phase which begins in December and ends in August; followed by the spawning which coincides with the increase of the sea water temperature (July and August). Sexual resting occurs immediately after the decreases of the sea water temperature in October. Through this study we concluded that the sexual reproduction cycle of the three studied gonochorics species, generally follows identical patterns to that already described for the majority of the aspidochirotid sea cucumbers inhabiting the temperate areas.