fisheries management, ARIMA model, CMSY, illegal fishing, northern Arabian Sea, Science, General. Including nature conservation, geographical distribution, QH1-199.5

Effective fisheries management is crucial for the sustainable use of fishery resources, increasing relying on stock assessments. The Megalaspis cordyla an economically important fish species in Pakistan, require an accurate assessment of its current biomass to take effective management strategies. This study utilized stock assessment techniques, including the Catch-Based Monte Carlo Maximum Sustainable Yield (CMSY), length-based Bayesian Biomass (LBB), Just Another Bayesian Biomass Assessment (JABBA), and ARIMA models. While CMSY, BSM, JABBA, ARIMA rely on annual catch-effort data, while LBB analyzes length-frequency data along with resilience inputs. An analysis of 15 years of catch data (2007-2021), and 1,442 length-frequency data from Pakistani waters revealed that the fishery is overfished both in terms of exploitation and biomass (LBB at F/M = 1.6, B/BMSY = 0.76 and B/B0 = 0.27). The CMSY method estimated biological reference points as r = 0.53, k = 231, and a maximum sustainable yield (MSY) of 3.06. In comparison, the BSM provide values of r =0.03, k =271, MSY = 2.56. The JABBA model estimated MSY of 3.637, with a biomass to MSY2021 (B2021/BMSY) of 0.68 and F2021/FMSY of 1.56, indicating excessive exploitation. The projected biomass ratio (B2021/BMSY) of 0.798, is