Population dynamics of Labeo senegalensis Valenciennes 1842 (Pisces: Cyprinidae) in the Oueme River, Benin

he present study was conducted to understand the population parameters of Labeo senegalensis in Benin. Growth and mortality parameters, exploitation rates and annual recruitment patterns were estimated from monthly length-frequency samples between April, 2005 and March, 2006 for Labeo senegalensis in the Oueme river. Total length of the sampled 1436 fish ranged from 6.3-52.7 cm. The Von Bertalanffy Growth Function (VBGF) was fitted to the 12 consecutive month’s length-frequency data to obtain a VBGF with the following parameters: L∞ = 57 cm TL, K = 0.30 year-1. The growth performance index (ø') was calculated as 2.99. The total mortality estimates from the catch curve analysis was Z = 1.47 year-1 with a natural mortality M of 0.68 year-1 for a mean environmental temperature of 28°C. The fishing mortality F estimates was 0.79 year-1. The maximum of recruitment was recorded in June to September, indicating recruitment of one cohort year-1. The estimated potential longevity Tmax was 10 years. The exploitation ratio was 0.55 indicating that the Labeo senegalensis stock is on the verge being overfished. The results are discussed and compared to previously available information on Labeo senegalensis in others rivers.