Growth, exploitation and mortality parameters of mangrove oyster Crassostrea gasar of Grand-Lahou Lagoon (Côte d’Ivoire)

Abstract

This study on growth, exploitation and mortality parameters of the mangrove oyster in the Grand-Lahou Lagoon was conducted from February 2019 to January 2020. Thus, a monthly sampling of 60 oysters coupled with water temperature measurement was carried out. Parameters were determined from the 20 mm size frequencies and integrated into the FiSAT I I software. Oysters from the Grand-Lahou lagoon have an asymptotic length of 142 mm, a growth coefficient (K) of 0.85 year-1, and a growth performance index of 2.234. Total mortality, natural mortality and fishing mortality are 2.26 year-1, 2.01 year-1and 0.25 year-1, respectively. Survival rate is 0.104 year-1, the exploitation rate (E) 0.11 and longevity (tmax) recorded is 3.53 year-1. Oyster recruitment is continuous throughout the year with two peaks, the largest in April and the lowest in October. Results from this study could contribute to the sustainable exploitation of this aquatic resource.