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.

Some Biological Characteristics of Chrysichthys nigrodigitatus from Luubara Creek, Niger Delta, Nigeria

“…The growth performance index, Ø exhibit close values within species and closely related taxa. This is similar to the result of Kone et al (2022) andkongbeh et al, (2015) for C. nigrodigitatus in diferent locations in Africa. For the close species, Chrysichthys auratus, growth performance index was 2.55 (Abdellatif et al, 2022).…”

“…This implies that the higher the growth coefficient the faster the silver catfish approaches the asymptotic length. The Asymptotic length in this study is greater than those found for the same species by Kone et al (2022), Kongbeh et al (2015, but closer to Ajagbe et (2021). The implication is that Fish with a smaller asymptotic length may initiate reproduction earlier, potentially allowing them to support a larger biomass in comparison to individual with larger length (Ahti et al, 2022).…”