Abstract

The present study of the rreproductive cycle of Strombus gigas at San Andres, Providence y Santa Catalina, Colombia revealed a problematic situation in this population. Samples were obtained by a cooperation program “Estrategias reproductivas del Caracol pala Strombus gigas en el Caribe Insular colombiano” No. 003/abril, 2003, between Departamento Archipiélago de San Andrés, Providencia y Santa Catalina, Colombia and Laboratorio de Biología y Acuacultura de Moluscos, CINVESTAV IPN Mérida, Yucatán, Mexico. 311 organisms were analyzed from February 2003-to January 2004, with a shell length ? 230 mm. Samples from visceral mass and gonad were taken and processed for histological study. Gametogenesis was observed all year round but at a low percentage. Mature stage was observed only in August-September with percentages ? 10%. Such a detrimental situation may be related to an intense and generalized putative sporozoan infection detected in the sampled S. gigas population. The parasite, apparently a Coccidian was found in the digestive gland of every sampled organism throughout the year, infecting from 70% to 100% of the digestive gland alveoli, with a frequent total invasion of every alveolar cell. This infection may be responsible for the low intensity of maturity and scarce spawning stages registered at San Andres Archipelago. However, the actual knowledge of spatial and temporal variations of the reproductive cycle of S. gigas and of its parasitic status is not sufficient to propose an efficient management for its sustainable exploitation. Complementary studies appear necessary and urgent to understand its biological status throughout the reproductive cycle. Meanwhile, a mandatory minimal catch size could be a lip thickness > 7 mm in order to protect the endangered reproductive stock of S. gigas at San Andrés. The level of protection will depend on an efficient survey and protection of the populations and a high enforcement of regulations to control exploitation and reduce illegal fishing.

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