Reproduction of the biogenic reef-forming honeycomb worm Sabellaria alveolata in Ireland

The stage of development of the gametes of both male and female honeycomb worms Sabellaria alveolata (L.) was examined, using histology, over a 14-month period. Samples came from Howes Strand and Garrettstown, County Cork in south-west Ireland. A clear cycle of both male and female gametogenesis was evident, with a distinct peak in the summer (June-September) when the majority of them were ripe. During October-January a small proportion of males contained abundant spermatozoa, but no mature oocytes were found. Over the whole sampling period the ratio of males:females was 1.4:1. Further south in Roches de la Fosse in France at the centre of its range, two spawnings and an even sex-ratio have been reported.