Stock status and spawning potential ratio of orange mud crab (Scylla olivacea, Herbst 1796) in the southwestern coastal waters of Bangladesh

<i>Scylla olivacea</i> (Orange mud crab) is a second commercial invertebrate species exported from Bangladesh. Though a significant portion of exports are supported by aquaculture, their farming ultimately depends on their wild stocks. Unfortunately, unregulated exploitation has led to a significant decline in the natural biomass of this species, raising concerns about the sustainability of crab production in Bangladesh. The study aimed to assess the stock status of <i>S. olivacea</i> (Orange mud crab) from the Southwestern coastal water of Bangladesh. One-year length frequency (width frequency-WF for crustacean fishery) data were collected and analyzed using the LBB (Length-based Bayesian Biomass) and LB-SPR (Length-based spawning potential ratio) methods. The assessed width parameter depicted the exploitation of small-size individuals (<i>W</i> _<i>c</i> <i>=< W</i> _{<i>c_opt</i>} ) of <i>S. olivacea</i>. The estimated <i>B/B</i> _<i>0</i> (0.25) suggests that 75 % of the wild stock had already been harvested, and biomass cannot produce MSY. The mean estimates for <i>SW</i> _{<i>50 %</i>} and <i>SW</i> _{<i>95 %</i>} were 8.29 cm and 12.76 cm respectively, revealing the use of a small mesh-size net for crab harvesting. The assessed Spawning Potential Ratio (SPR) was 12 % which is below the SPR limit reference point (SRP) of 20 %. This research confirmed the overfished (<i>F/M</i> = 1.4) and overexploited (<i>E</i> = 0.58) status of <i>S. olivacea</i> in Bangladesh. To ensure the sustainability of coastal fisheries in Bangladesh, the authorities must take immediate management measures to control the overexploitation of this species.