Length-frequency based stock assessment of Puntius sophore(Hamilton, 1822) in Kasaraiya Dhar Wetland, Bihar, India

Abstract

The population dynamics of Puntius sophore was investigated in Kasaraiya Dhar Wetland, Bihar, India, using monthly sampling (n=149) over a period of one year. Length–frequency data of P. sophore were analyzed using the FAO-ICLARM Stock Assessment Tools II (FiSAT II). Growth parameters, including asymptotic length (L∞) and growth coefficient (K) were estimated through ELEFAN on von Bertalanffy Growth Function. The estimated growth parameters were asymptotic length (L∞) = 102.90 mm, growth coefficient (K) = 0.65 yr⁻¹ and length at zero age (t₀) = –0.177 yr. The positive allometric growth length-weight relationship (W = 2E-06L3.4158; R² = 0.9345) and Fulton’s condition factors (1.0169 and 1.0446, respectively) indicated favourable habitat conditions for P. sophore in
Kasaraiya Dhar. Natural mortality (M) was estimated at 0.93 yr⁻¹, total mortality (Z) at 1.75 yr⁻¹ and fishing mortality (F) at 0.81 yr⁻¹. Exploitation ratio (E = 0.40) confirmed that P. sophore stocks were currently underexploited relative to the optimum of E= 0.5. The dominance of natural mortality over fishing mortality reflected limited fishing efficiency due to dense macrophyte cover, which provides refuge and breeding habitat. Overall, the study indicates that P. sophore populations in Kasaraiya Dhar are in good condition and were being moderately exploited under prevailing ecological conditions. Macrophyte management needs to be prioritized to support recruitment and achieve for maximum sustainable yield P. sophore from Kasaraiya Dhar. The findings provide essential baseline information for future stock assessments and for developing strategies aimed at the rational and sustainable exploitation of this species.