Population dynamics and stock assessment of two major eels (Muraenesox bagio and Congresox talabonoides) from the marine waters of Bangladesh

Muraenesox bagio (black eel) and Congresox talabonoides (brown are two major eels (Muraenesocidae) species which commercially significant in the marine catch of Bangladesh, but population dynamics stock assessment eel fishery Bangladesh yet to be studied. This study is first endeavour analyze this collected from July 2021 May 2022 using three length-based methods namely TropFishR, Length Based-Spawning Potential Ratio (LB-SPR) & length-Based Indicators (LBI) catch-based including Depletion-Based Stock Reduction Analysis (DB-SRA) Catch-Maximum Sustainable Yield (CMSY). A slightly positive allometric growth pattern ( b =3.10) for black a negative =2.33) brown were observed length-weight relationship. The parameters von Bertalanffy Growth Function (VBGF) linearized length-converted curve (LCCC) analysis L ∞ = 190.67cm 166.63cm, k =0.18 year -1 0.16 , total mortality, Z =0.70 0.45 . calculated overfished due overexploitation stock’s spawning biomass SPR =19% 21% close limit reference point well outside targeted range because majority catches found have below-maturity levels. advised an optimum length 93 114 cm 83 101 eel. Though estimated points CMSY more optimistic than those DB-SRA, tendency status has been displayed moving towards safe scenario. study, therefore, recommended annual landing 250 mt as OFL (Over fishing limit) next ten years association with existing management measures maintain present over B MSY level.