Reproductive patterns of the coral Pocillopora damicornis at Gorgona Island, Colombian Pacific Ocean

Abstract

Knowing the gametic development of the coral Pocillopora damicornis and its relationship to environmental variation at La Azufrada reef (2°58′10″N and 78°11′05″W, Gorgona Island, Colombian Pacific Ocean) is essential to understanding the capacity for sexual replenishment of this population. Due to the lack of information about its sexual reproductive process, we collected tissue samples of healthy and unhealthy colonies (with bleaching, or algal or cyanobacterial overgrowth), along with salinity and sea-surface temperature data, between October 2010 and October 2011. During histological analysis we observed four oocyte and three spermary developmental stages in healthy colonies. Colonies were hermaphrodites with synchronous gonadal maturation in May 2011. However, polyps within colonies were either gonochoric, with a 7.8 ± 11.8:1 (mean ± SD) female to male polyp sex ratio, or hermaphroditic, with a 2.8 ± 1.5:1 (mean ± SD) oocyte to spermary ratio. The low number of spermaries observed may reduce the chance of effective fertilization and could explain the low sexual recruitment observed in the study area. There was a positive correlation between salinity and the mean number of gametes (oocytes and spermaries) produced per polyp, although both oocytes and spermaries increased during the warm water, high-salinity season (March to July 2011). Colonies with bleaching or overgrowth by cyanobacteria or algae had no gametes, suggesting that population recovery after disturbances might not be effective if it depends solely on sexual reproduction.

Key words:

• Gametogenesis
• Pocillopora damicornis
• reproductive seasonality
• sexual maturity
• Tropical Eastern Pacific

Acknowledgements

We thank the Special Administrative Unit of National Natural Parks for providing research permits, and the Henry von Prahl Scientific Station of the National Natural Park Gorgona and its staff, particularly Ximena Zorrilla, for logistical support. We gratefully acknowledge Michelle Casad for checking the English language of a previous version of the manuscript, and the comments of two anonymous reviewers who helped improve the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Editorial responsibility: Tina Molodtsova

Additional information

Funding

This study was funded by a Colombian Department of Science, Technology and Innovation (COLCIENCIAS) grant (number 1106-489-25135) awarded to F.A. Zapata and was co-supported by Universidad del Valle.