Reproduction in the externally brooding sea anemone Epiactis georgiana in the Antarctic Peninsula and the Weddell Sea

• Published in: Marine Biology
• Main Authors: Rodríguez, Estefanía, Orejas, Covadonga, López-González, Pablo J., Gili, Josep Maria
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer 2013
• Subjects: Antarctic; Antarctic Peninsula; Austral; Daly; The Antarctic; Weddell; Weddell Sea; Antarc*
• Online Access: http://hdl.handle.net/10261/72350; https://doi.org/10.1007/s00227-012-2063-x

14 pages, 8 figures, 2 tables External parental care is uncommon among actiniarians but common in Epiactis species. Here, several aspects of reproduction are analyzed for of one of them, Epiactis georgiana. Samples were collected in December, January, February, March, and April in the Antarctic Peninsula and the eastern Weddell Sea, during 1998, 2000, 2002, and 2003. Most sexually mature individuals of E. georgiana are male or female, but some are hermaphrodites. This is the first report of hermaphroditism in E. georgiana, which is the third species of the genus with this sexual pattern. The results suggest that oogenesis starts in December and that at least two generations of oocytes overlap; a third generation is often brooded externally. Putative fertilization is likely internal, and larvae and/or embryos are externally brooded on the distal part of the adult column until an advanced developmental stage. Apparently E. georgiana reproduces seasonally, probably releasing the embryos/larvae in the last months of the austral spring (December). Inter-individual variability was observed in gametogenesis. In addition, specimens from the Antarctic Peninsula were larger than those from the Weddell Sea. This study represents the first step in understanding the reproductive mode of E. georgiana Special thanks are addressed to Prof. Dr. Wolf Arntz (Alfred-Wegener-Institute, Bremerhaven, Germany) who made possible our participation in several Antarctic projects and cruises. We extend our acknowledgements to the officers and crew of the R/V Polarstern and many colleagues on board during the EASIZ, ANDEEP, and BENDEX cruises for their valuable assistance. Thanks to M. Conradi (Universidad de Sevilla) who collected a considerable amount of the material analyzed in this manuscript. Comments from M. Daly, D. Fautin, and an anonymous reviewer substantially improved this manuscript. Support was provided by a MCT-CSICgrant (I3P-BPD2001-1) to E. Rodríguez and Spanish CICYT projects: ANT97-1533-E, ANT98-1739-E, ANT99-1608-E, ...