Status Review Of Fish Fauna Of Loktak Wetland Complex With Reference To Changing Dynamics Of The Wetland Ecology.

Abstract

Loktak Lake – a Ramsar site of international importance – is a key biological diversity site in Manipur, India, being an important feature of wetland ecosystem within two significant global biodiversity hotspots, namely, the Eastern Himalaya and the Indo-Burma Biodiversity Hotspots. The Loktak Lake, a composition of several separate wetlands converged into a single spread of water by artificial regulation of Ithai Barrage for the 105 MW capacity Loktak Hydroelectric Power Project, is currently undergoing changes influenced by physical modifications, siltation, pollution, and eutrophication enhanced by inflow of chemical residue from nearby paddies and pollutant effluent discharge from urban and peri-urban areas. Extensive use of chemical fertilizers and pesticides by farmers in peripheral agricultural fields, and their runoff thereof, along with pollutant effluent feed from direct in-flowing rivers like Nambul, Nambol and Moirang has accentuated the pace of degradation of the wetland ecology. A visible example of physical changes taking place is the rapid spread of invasive aquatic plants and weeds which are overcrowding the water body of the lake and posing threat to native species of food and medicinal plants traditionally harvested by local people for food, and for their livelihoods. At the same time, it is observed that fish fauna population in the lake has declined considerably owing to these influences. The paper attempts at understanding the human induced impacts on the lake ecology, the plant and animal lives, and upon the local fishing community by the changes taking place since the commissioning of Ithai Barrage in 1983. The methodology is empirical in design being based primarily on observations in field and through interaction with local fishing families. The suggested pathway is for rapid assessment of the current status of Loktak wetland complex, and, thereto, in finding ways to minimize the changes taking place through scientific intervention and community participation.