This study provides an overview of the seasonal variation on catch composition, the pattern of gear used and their effects on fish production and management system of north-western part of the Chalan beel. Results of the study revealed that annual beel cycle can be divided into four phases namely, resting, preparatory, growing and decay. Harvesting of fishes in chalan beel was done by using a variety of fishing gears. A total of 27 different types of fishing gears were recorded during investigation period from the study area of the beel. Recorded fishing gears were categorized into three major types which were net, trap and wounding gear. Marked seasonal variation was observed in the use of gears which mostly dependent on the flooding and water depths of the beel. A total of 62 fish species were recorded from this study area including 51 indigenous fish species and 11 exotic species. Fishes were recorded under following 12 fish orders-Cypriniformes, Siluriformes, Perciformes, Channiformes, Mastacembeliformes, Clupeiformes, Osteoglossiformes, Cyprinodontiformes, Anguiliformes, Synbranchiformes, Beloniformes and Tetraodontiformes. Some gears like Shuti jal, Current jal, Khora jal, Ber jal/Badai jal and some traps and specialized fishing methods were identified as very harmful to the sustainable production of the beel as well as to the wild brood stock of these natural water bodies. About 8 fish species were recorded as threatened species due to irresponsible fishing. Overall fish production level of the study area was not satisfactory which ranged from 350-400 kg/ha/yr.