Decadal Shift in Fish Landings and Catch Composition in Brahmaputra River, Assam, India

Abstract

Analysis of long-term (1987-2019) fish landing data showed that an average 191.93 t year -1 of fish landed at Uzanbazar (Guwahati) landing center of River Brahmaputra. The total landings registered peak landings of 471.8 t in 2002 and thereafter it declined to the lowest levels of 84.06 t in 2016. Fish landings suffered changes in the qualitative and quantitative aspects of River Brahmaputra fishery in Assam. Whereas average total landings during last decade declined by almost 60% as compared to the average landings of 234.97 t year -1 in the previous two decades , the contribution of Indian major carps (IMC) and minor carps towards total landings declined from 17.54% and 35.11% during 1987-2009 to only 4.86% and 8.94%, respectively during 2010-2019. Miscellaneous fishes group emerged as dominant group contributing 58.28% of the average landings in last decade (54.30 t year -1 ) compared to 69.38 t year -1 during 1987-2009. Average landing of catfishes also decreased from 26.96 t year -1 in 1987-2009 to 19.77 t year -1 in 2010-2019, but percentage contribution increased from 11.47% to 21.28% over decades. Similarly, average landings of Hilsa declined from 8.24 t year -1 to 3.42 t year -1 but percentage contribution remained unchanged over the period. Such changes can be partly ascribed to climate change, habitat modification, over exploitation and other anthropogenic causes. The sharp decline in IMC landings as well as changes in landing composition from the river due to these alterations in the last decade is directly affecting the livelihood of the fishermen community.