Population parameters and exploitation levels of Synodontis membranaceus, a commercially valuable species in the Bagoué River in northern Ivory Coast

The aim of this study is to determine the population parameters and exploitation level of Synodontis membranaceus in the Bagoué River in northern Côte d’Ivoire. A total of 690 specimens were collected every two months from August 2018 to February 2020. These specimens came from both commercial and experimental fishing. The sampled individuals ranged in size (LS) from 6.2 cm to 23.5 cm. Analysis of the size frequency distribution using FiSAT II software yielded growth parameters such as L∞, K, and to with respective values of 26.11 cm, 0.64 year-1, and -0.26 year-1. The natural mortality (1.38 year-1) observed is higher than fishing mortality (1.34 year-1). The exploitation rate (E = 0.49), which is below the optimal exploitation rate (E = 0.5), shows that the species is under-exploited. It would therefore be beneficial to maximize fishing activities for this species in order to reach its optimal rate. However, as natural mortality for this species is higher than fishing mortality, this should prompt researchers and decision-makers to conduct further research into the factors responsible for this natural mortality and take measures to prevent the decline of this species