Life-history traits of a common Caribbean coral-excavating sponge, Cliona tenuis (Porifera: Hadromerida)

Abstract

Clionaids are important competitors and bio-eroding agents on coral reefs; however, little is known of their biology. We studied aspects of life history of Cliona tenuis, in particular its sexual reproduction and growth. Temporal variations in these traits were studied over a year, in correlation with water temperature as a proxy for seasonality. Growth and sexual reproduction occurred at separate times and followed intra-annual variations in temperature. Growth increased during the warmest months of the year, reaching an average rate of 29.9 ± 6.7 mm during 286 days. Cliona tenuis is oviparous, and the results suggest gonochorism. Gametogenesis occurred between the coldest months and the period when temperature was increasing. Recruitment was constant throughout the year, possibly associated with post-settlement processes. Juvenile-size individuals were represented in the studied population, suggesting that processes like competition and mortality may control the population, whose size structure may be sustained by high recruitment rates.

Keywords:

• Porifera
• Cliona
• bio-erosion
• reproduction
• life cycle
• recruitment
• growth
• Glover’s Atoll
• Belize

Acknowledgements

The authors would like to acknowledge the contribution of the anonymous reviewers whose contribution greatly improved this manuscript. We thank the Fondo Nacional de Ciencia, Tecnología e Innovación (FONACIT, Venezuela), the Wildlife Conservation Society (WCS, USA) and the Khaled bin Sultan Living Oceans Foundation (LOF, USA) for funding this project. We are also grateful to Dr Darryl Whitehead and Prof. David Merritt for the use of the histology and microscopy facilities at the schools of Biomedical Sciences and Biological Sciences, University of Queensland (Australia), and to Dr Alvine Mehinto and Prof. Charles Tyler, at the College of Life and Environmental Sciences, University of Exeter (UK), for providing facilities for the histological processing of samples. Iliana Chollett extracted and processed the data for SST.