Vol. 1, Issue 7, Part B (2015)

Abstract
Indigenous fish varieties found in rivers and beels of Kokrajhar district provides livelihood support of the people of the region. Most of the local fishes are brought from different Beels, Rivers, Ponds and Agricultural crop land to the daily market. But due to some unplanned fishing activity and anthropogenic pressure on the aquatic ecosystem the major fish varieties are dwindling day by day and sometimes severely get infected with certain diseases. The present investigation revealed the potential cause of the dermal lesion of Puntius sp. of Tarang River which causes tremendous loss annually. Clinically, cotton wool type lesions on the fish body surface, ulceration and erosion of skin and muscles were observed. The agricultural runoff during monsoon and dumping of household’s garbage are the some major source of the pollution of the Tarang River. Diseased Puntius sp. were tested in the laboratory with an aim to identify the possible cause of the disease and exploring the ecological status of the said river canal.