Estimating some population parameters and stock assessment of Dark Sleeper Odontobutis potamophila in the Gaosha River, Wuyuan County, Jiangxi Province, China

A study was conducted to investigate the growth parameters, mortality and recruitment pattern of Odontobutis potamophila collected in the Gaosha river fish landing site, west part of Wuyuan County (Latitude: 29°X 14 ’29 ” N, Longitude: 117°X 45 ’49 ” E). O.potamophila were collected from November, 2013 to October, 2014. Growth parameters, asymptotic length (L∞ = 192mm and growth coefficient (k) = 0.22 year-¹. Growth performance index(Φ) =3.91, total mortality (Z) = 0.72 year-1, natural mortality (M) = 0.32 year-¹, fishing mortality (F) = 0.40 year-1 and exploitation rate (E) = 0.55year-¹. The estimated exploitation rate (E) has slightly exceeded the optimum value of E indicating this species was sustainable exploitation in the study area. The exploitation ratios were computed as E_max= 0.61, E₁₀= 0.52, E₅₀= 0.34. The length at first capture at 50%, (Lc) was 77 mm. The recruitment pattern of the species was found continuous all-round the year with one peak. The observation of the annual recruitment of O.potamophila found to occur from May to July. Steady biomass also increased with length class until 121–125 mm, and the total steady state biomass was found to be 2240 kg.