Length-weight relationship and condition factor of Chrysichthys nigrodigitatus in two hydrosystems of northern Ivory Coast

Sustainable management of fish stocks requires a good knowledge of growth parameters.The Nangakaha and Sologo dam lakes are subject to numerous anthropogenic disturbances that have manifested themselves in recent decades by a massive and sudden mortality of the fish population.In order to measure the impact of these disturbances, the length-weight relationship and the condition factor were analyzed for Chrysichthys nigrodigitatus on these lakes.The objective of this study is to contribute to the study of the growth of C. nigrodigitatus on the Nangakaha and Sologo lakes.1800 specimens in Nangakaha and 357 in Sologo were sampled during this study, from commercial catches.After identification, each specimen was weighed and measured.The results of this work show that all individuals have negative allometric growth (b = 2.45 in Nangakaha and 2.65 in Sologo).A strong correlation (r = 0.90 in Nangakaha and r = 0.85 in Sologo) between weight and length was also noted.The average condition factor was lower in Nangakaha (2.39) than in Sologo (2.35).In Nangakaha, specimens with a size range [8-9 cm] (21.56%) were the most numerous, while in Sologo, those with sizes in the range [9-10 cm] (28.29%) dominated the population.