The coastal ecosystem of the Bay of Bengal (BOB) is described using a mass balance model of trophic interactions, in order to understand the effects of Set Bagnet (SBN) on the environment. ecosystem. The BOB model covered an area of ​​24,000 km2 and had 14 functional ecological groups including 13 living groups and one dead group (detritus). The result showed that all consumers had an ecotrophic efficiency (EE) >0.90, indicating that consumers were heavily exploited in the system. The fishery operated at an average trophic level of 2.45. The SBN fishery was characterized by higher fishing mortality rates and high omnivory indices for most commercially exploited demersal and pelagic groups. For this fishery, the total primary production required for sustainable capture was estimated at 15.11%. However, Ecosim simulation results showed that key resources such as small demersal shrimp, small and medium pelagics and penaeids were likely to experience a rapid decline in yields within 5 years due to the increase in fishing effort and pressure. In contrast, yields of palaemonids and twill shrimp showed an increasing trend as they appear able to withstand the high fishing pressure as long as their predators are also caught. In addition, cephalopods, which are a non-target group by this fishery, are also expected to see their yield increase at present. The two groups most seriously affected in both fisheries were probably sharks and small demersals. The continued increasing fishing effort of the BOB has been shown to be causing a rapid decline in most commercial marine resources and has a serious effect on the functioning of the BOB ecosystem. Keywords: Bay of Bengal, Set Bagnet, High fishing pressure, yields, Ecosim.1. IntroductionBangladesh has v...... middle of paper ......mass (B) was carried out until the input equaled the output for each box. The gross efficiency and ecotrophic efficiency of all functional groups must be less than one. To achieve a mass balance for all groups, adjustments to diets were first made, because the feeding habits of some organisms are very labile and mainly depend on the food sources available in the ecosystem. The second step involved manual adjustments of biomass for different groups which were estimated by applying the weighted average method from survey data from several years. In Ecopath, trophic levels are the calculated output or results. If they do not conform to expectations, the food compositions of the input data can be checked. If in doubt about the trophic levels of fish, for example, one can check with FishBase the trophic levels of the same or similar species..