Reproduction in Octocorallia: Synchronous spawning and asynchronous oogenesis in the pennatulid Veretillum cynomorium

Abstract

Veretillum cynomorium is an abundant colonial octocoral that exclusively inhabits soft sediment and sandy substrata of the Eastern Atlantic Ocean, but its reproductive biology is completely unknown. Here we show, for the first time, that this sea pen is gonochoristic at colony level, and seems to reproduce sexually through the broadcast spawning of gametes. The duration of the present study (12 months) in the Sado Estuary, Portugal, allowed us to identify one brief synchronous spawning event. Mean oocyte size–frequency distributions indicated that large orange oocytes (>650 µm), and part of the intermediate-sized ones were released in July. The formation of new small (colorless) oocytes occurred in the post-spawning period, between August and October. However, individual oocyte size–frequency distributions of the colonies showed that there was no synchrony in late and early oogenesis. Fecundity ranged between 1 and 40 oocytes per polyp, with an annual average of 9 oocytes per polyp. The occurrence of sex ratios biased towards the dominance of female colonies is reported and discussed.

Keywords:

• Octocorals
• reproduction
• synchronous spawning
• asynchronous oogenesis
• sea pen
• Veretillum cynomorium

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Acknowledgements

The Portuguese Foundation for Science and Technology (FCT) supported this study through a Senior Research Position (Ciência 2007) to R.R.

Notes

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark