Reproduction of the intraovarian brooding apodid Leptosynapta clarki (Echinodermata: Holothuroidea) in British Columbia |
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| Authors: | M A Sewell F -S Chia |
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| Institution: | (1) Bamfield Marine Station, V0R 1B0 Bamfield, British Columbia, Canada;(2) Department of Zoology, University of Alberta, T6G 2E9 Edmonton, Alberta, Canada;(3) Present address: Department of Biological Sciences, Simon Fraser University, V5A 1S6 Burnaby, B.C., Canada;(4) Present address: Department of Biology, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong |
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| Abstract: | Reproduction in the viviparous apodid sea cucumber Leptosynapta clarki was examined in Grappler Inlet, Bamfield, Vancouver Island, Canada from July 1989 through July 1991. The reproductive cycle of L. clarki is annual with gonad growth during the summer months. Male sea cucumbers spawn during November and December and internally fertilize, through as yet undetermined means, the oocytes within the ovary. Embryonic development is rapid, so that within 2 wk fertilized eggs reach the pentactula stage. Pentactulae have an open mouth and anus and actively move in the ovarian tubules feeding on droplets and fluid derived from the resorption of unfertilized eggs. Histological examination of gametogenesis shows similar development to that found in non-brooding holothurians. However, the protandric sex change observed in some male L. clarki after spawning and changes to the overian wall structure prior to fertilization are previously undescribed in sea cucumbers. |
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