Growth, exploitation parameters and sexual maturity of Chrysichthys nigrodigitatus (Lacépède, 1803) downstream of the Taabo dam (Bandama River, Côte d’Ivoire)

Abstract

The objective of the present work is to study the growth, exploitation parameters and the size of first sexual maturity of Chrysichthys nigrodigitatus (Lacépède, 1803) landed in N'dènou, in order to evaluate the status of its stock. A total of 7635 fish were sampled monthly from November 2019 to October 2020. The individuals were measured, weighed and the data processed with the FiSAT II software. The calculated parameters are: allometry coefficient (b = 2.77); asymptotic length (L∞ = 51.98 cm); growth coefficient (K = 0.2 yr-1); growth performance index (φ' = 2.73); natural mortality (M = 0.54 yr-1); fishing mortality (F= 0.61 yr-1); total mortality (Z = 1.14 yr-1); exploitation rate (E = 0.53). The size of first capture is smaller than the size of first sexual maturity. Recruitment is continuous with the peak during the rainy season. The C. nigrodigitatus stock is under fishing pressure in the Bandama River.