摘要：Aquatic freshwater fish diversity immensely declines from several native places in West Bengal. Lots of freshwater fish have been extricated and some become endangered or vulnerable in condition as well as in Keleghai river. Aquatic ecosystem meltdown or crisis due to anthropogenic intervention resulted disappearance of eco-sensitive species. Such, appearance of Boal (Wallago attu) fish in this river was very common but now it's very amazing to see or to catch it. The number of this species decreased radically before some decades. The present study conducts an empirical investigation to find out the reasons are behind it. Lacking of printed information, the work concentrated on knowledge and perception of experienced fisherman for understanding the fact by interviewing method. After qualitative investigation, the study recommends that simplification of food web in this aquatic ecosystem is the major cause of abandonment of Attu fish in this river. Other important causes are advance unethical fishing techniques, habitat loss, and enormous use of chemical pesticide and fertilizer in wetlands.
