Reproductive cycle of the trigonal clam Tivela mactroides (Bivalvia, Veneridae) in Caraguatatuba Bay, southeastern Brazil

Abstract

Tivela mactroides is an important fishery resource for local artisanal fishermen in Brazil and the establishment of management programmes for this species requires information about its reproductive cycle, the main focus of this study. The reproductive pattern of T. mactroides from Caraguatatuba Bay on the southeast coast of Brazil was analysed by means of histological techniques from November 2003 to October 2004. The species had heterogeneous continuous gametogenesis, with no resting period and the sex ratio did not differ significantly from 1:1. Maturity indices varied over the months, with slightly higher proportions of mature gametes from May 2004 to October 2004, which indicates a high proportion of spawning in winter and spring; however, small releases of gametes may also have occurred during summer and autumn. As the reproductive cycle is heterogeneous and temporal seasonality in gametogenesis is not predictable, it is not possible to designate a closed fishing season for the present population as a management strategy to avoid overexploitation.

Key words:

• Reproduction
• sandy-beach
• spawning
• venerid

Acknowledgements

Thanks to the Centro Universitário da Fundação Octávio Bastos for logistical resources and to Dr Janet W. Reid, who revised the English text. We also thank four anonymous reviewers who made significant suggestions to the manuscript.

Editorial responsibility: Omar Hernando Avila-Poveda

Additional information

Funding

This work was partially financed by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) within the Biota/FAPESP – The Biodiversity Virtual Institute Program (www.biota.org.br). Thanks also to the Project AWARE Foundation and PADI Foundation for the grants for this research.