Reproduction and the unusual condition of hermaphroditism in Sarcophyton glaucum (Octocorallia, Alcyoniidae) in KwaZulu-Natal, South Africa

The genus Sarcophyton is an abundant soft coral on the marginal, high-latitude reefs in KwaZulu-Natal. A 2-year study on reproduction in the most common species, S. glaucum, revealed that gametogenesis in male and female colonies takes 9–10 and 16–18 mo, respectively, in this gonochoric, seasonal, broadcast spawner. Gametogenesis and spawning are synchronised in and between colonies, and with other common soft corals on the reefs. Spawning occurs annually in March between full and new moon with the release of spermsacs and the mature oocytes, the smaller oocytes being retained for further development. Thus far, the reproductive attributes of S. glaucum are comparable with other studies on the genus. However, the KwaZulu-Natal population of S. glaucum manifested the unusual attribute of hermaphroditism in 9% of the colonies, these having Stage I and II spermaries and predominantly Stage III and IV oocytes in their polyps. Small numbers of Stage I and II oocytes indicated that such colonies may be simultaneous hermaphrodites but this could not be confirmed. The complex reproductive strategy and associated measure of hermaphroditism in S. glaucum on KwaZulu-Natal reefs are discussed in terms of the species’ recruitment success in this marginal, high-latitude environment.