Reproductive cycle of venus clam Chione undatella in the coasts of the Santa Rosalia mining region, Baja California Sur, Mexico

Background: The organisms respond to changes in the environment, hence the reproductive process of an organism can be affected as a result of contamination. Chione undatella is a potential resource for fishing and cultivation, which has been intensively exploited for many years on the Mexican Pacific coast. Goals: The main objective of this study was to characterize the reproductive cycle and spawning temporality, estimate the size at first maturity, and determine if there is tissue damage that may have adverse effects on reproduction of C. undatella because of the contamination found in the mining port of Santa Rosalia, Gulf of California. Methods: Through histological analysis, the general condition index (GCI), and environmental parameters, we evaluated aspects of the reproductive biology and health of the frilled venus clam from the coastal area of the port of Santa Rosalia. Results: C. undatella has reproductive activity throughout the year, unrelated to the concentration of chlorophyll-a, or to temperature. An inverse correlation was found between the GCI and the phase of development with higher frequency in females. The size at first maturity is 57 mm LC. In the gonadal tissue (> 80% of the individuals) an infiltration of eosinophilic cells was observed in all phases of gonadal development with an intermediate to abundant intensity (> 60% of the organisms). Conclusions: Although C. undatella has reproductive activity throughout the year, the high prevalence of hemocytic infiltration in the gonadal tissue suggests a potential deficiency in its reproduction. We recommend more studies be undertaken to confirm this preliminary finding and determine the relationship of the deficiency with the contamination present in the area.