Relative Growth and Morphometric Characterization of Mangrove Oyster, Crassostrea gasar of the Lagoons Ebrié and Aby (Côte d'Ivoire)

This work characterizes the growth of mangrove oyster, Crassostrea gasar of two lagoons of Côte d’Ivoire: the Ebrié lagoon; on the level of Grand-Bassam and Azito and the Aby lagoon; on the level of Assinie. Thus, a monthly sampling of 30 oysters per site for 12 months (October 2015 at September 2016), during which the physico-chemical parameters of water were recorded. The results of the study show an almost similar evolution of the physico-chemical parameters of the three sites. However, the sites of Assinie and Azito recorded a salinity, although lower than 10‰, high compared to that of Grand-Bassam. The results of morphometric analyses plead in favour of a negative allometry for the two relations in particular, size-sizes relations and size-weight relations. However, the individuals of Assinie present the best values of growth coefficient (b). According to PCA, the individuals of Assinie are identifiable by a weight of flesh and a width of higher bodies. Those of Azito are characterized by a thickness of body, a weight of shell, and a body weight more marked. As for the individuals of Grand-Bassam, they don’t present any distinguishing mark making it possible to characterize them. This study shows, the necessity to install a durable strategy of management of oyster stocks of our lagoons. It would be interesting to envision the culture of the oyster which remains an important food product of socio-economic interest