2017, Vol. 2 Issue 2, Part DECEMBER
Population parameters and exploitation rate of two dominant fish species in Tovè River (Southern Benin)
Author(s): Gildas Djidohokpin, Edmond Sossoukpè, Richard Adandé and Emile D. Fiogbé
Abstract: Most fisheries in Africa are overexploited or are at the peak of exploitation. A key contributor to this over fishing is poor data on fisheries, inefficient management strategies and unenforced policies. This study deals with growth, mortality parameters and the exploitation rate of Synodontis schall and Shilbe intermedius collected with a range of several fishing gears between October 2015 and September 2016 from Tovè River in Benin to contribute to sustainable management of these fisheries. The von Bertalanffy growth constants for S. schall were TL∞ = 21.84 cm, K = 0.93 yr-1, and t0 = -0.49 yr with a derived growth performance index of j'= 2.64. The corresponding estimates for S. intermedius were TL∞ = 25.20 cm, K = 0.52 yr−1, t0 = -0.52yr and j' = 2.51. The total mortality rate, Z, for S. schall was estimated as 4.13 yr−1, with the fishing mortality, F, being calculated as 2.31 yr−1. The mortality estimates for S. intermedius were Z = 1.28 yr−1 and F = 0.08 yr−1. The size at first capture was estimated at 5.35 cm and 7.20 cm for S. schall and S. intermedius, respectively. The current exploitation rates for S. schall (0.55) and S. intermedius (0.06) suggest that only the stocks of S. schall was slightly above the assumed optimum value (Eopt = 0.5). Rational measures must be taken to effectively manage for exploitation of these 2 stocks particularly the one of S. schall.