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Marine Ecology Progress Series

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MEPS 224:87-92 (2001)  -  doi:10.3354/meps224087

Age-dependent loss of fertility in water-borne sperm of the bryozoan Celleporella hyalina

P. H. Manríquez1, R. N. Hughes1,*, J. D. D. Bishop2,3

1School of Biological Sciences, University of Wales, Bangor, Gwynedd LL57 2UW, United Kingdom
2Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth PL1 2PB, United Kingdom
3Department of Biological Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, United Kingdom
*Corresponding author. E-mail:

ABSTRACT: The cheilostome bryozoan Celleporella hyalina (L.) was used as a model to test the hypothesis that sessile animals fertilising retained eggs by water-borne sperm should produce sperm with relatively prolonged fertility during the dispersal phase. Ramets of each of several recipient clones were exposed to suspensions of allosperm obtained by induced release from ramets of donor clones. Allosperm was presented to each series of ramets at a concentration of 10 to 102 ml-1, in aliquots of increasing age after release. Control ramets of the recipient clones isolated from allosperm failed to produce embryos, indicating the absence of autogamy. Experimental ramets exposed to fresh allosperm copiously produced embryos, but the frequency of embryos declined sharply in ramets exposed to allosperm suspension of increasing age. The estimated fertile half life of water-borne sperm was 1.2 h, which is at the upper limit of the range of values reported for other marine animals at comparable concentration. C. hyalina maximises fertilisation success by efficient dissemination, capture and storage of relatively long-lived sperm.

KEY WORDS: Free-spawning · Allosperm · Allogamy · Sperm storage · Cloning

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