Stock status of Hepsetus odoe (Bloch 1974) in river Imo, Nigeria, for conservation and management strategies for sustainability

The fisheries stock status: growth, recruitment rates, Maximum Sustainable Yield (MSY), Mortality and Exploitation rate of Hepsetus odoe in river Imo, Nigeria were investigated. Assorted fishing gears with mesh sizes(15 – 30 mm) were used to catch fish in designated 4 sampling stations of River Imo from January to July 2023. Standard lengths (S.L.) of 131,226 specimens of H. odoe were taken to the nearest centimeter (cm) and analyzed with Electronic Length Frequency Analysis (ELEFAN II) then fitted into the Von Bertalanffy Growth Model (VBGM). The estimated VBGM was L(t) = 55.65[1 – e -0.24(t – 0.9)]. The estimated growth parameters value was for L∞ = 55.65 cm; Total Mortality (Z) = 1.21 yr-1, Natural Mortality (M) = 0.52 yr-1, Fishing Mortality (F) = 0.69 yr-1 and Exploitation rate (E) = 0.57 yr-1. H. odoe was slightly over-exploited in River Imo, being that estimated Exploitation maximum (Emax) was 0.52 yr-1. The Relative Yield per Recruitment (Y’/R) indicates that the fishery is not operating at its MSY. The Reproductive load indicated over-fishing. There should be restrictions on the mesh sizes in use and closed fishing season of H. odoe in the identified recruitment peak of the month of June, every year to avoid the collapse of the species’ fishery in River Imo which may threaten the current conservation status of the species by International Union for Conservation of Nature (IUCN)