Cycle of gonadal development in Eunicella singularis (Cnidaria: Octocorallia): trends in sexual reproduction in gorgonians
Ribes, M.; Coma, R.; Rossi, S.; Micheli, M.
2007
Invertebrate Biology
126
4
307-317
Eunicella singularis is a gorgonian species whose members are abundant in hardbottom sublittoral communities of the Mediterranean Sea. The reproductive biology in this species has been examined to better understand the ability in this species to recover from recent mass mortality events. Eunicella singularis is a stable, gonochoric, iteroparous species that reproduces annually and exhibits a seasonal pattern of gametogenesis characterized by a single annual maturation of the gametes. The sex ratio did not significantly differ from 1:1. Oogenesis lasted 1317 months, beginning between February and June, and ending with the release of 0.7 planula larvae per polyp between late May and July of the following year. The diameter of mature oocytes ranged 450860 mm. Spermatogenesis was much shorter than oogenesis and occurred over 56 months. Gonadal production of both sexes increased in spring and culminated with the spawning of male colonies in late MayJune. Fertilization of oocytes and development of the planula larvae occurred within the polyps of female colonies. Planula release was observed in June and July. The patterns emerging from this and previous studies on sexual reproduction of Mediterranean gorgonians suggest that investment in gonad development appears to be related to resource availability.
gorgonians, sexual reproduction, sex ratio, gametogenic cycle