Biplab Kumar Das1 and Mofidul Islam2

1Department of Zoology, Jengraimukh College, Majuli-785105 (India) 2Department of Zoology, PDUAM, Behali-784166 (India) E-mail:


The unique topography of North-East India and its watershed pattern is an attractive field for fish fauna studies. This region has all been recognized as a global spot of freshwater fish diversity. Many species have been reported from most of the North-Eastern region states. River Siang is one of the major rivers of Arunachal Pradesh. The present study on Icthyofaunal diversity of River Siang in Arunachal Pradesh was carried out from June 2012 to July 2013. Fishes are very important from a biodiversity point of view. The present Studies on River Siang reveal the presence of 82 (Eighty-Two) species of fish belonging to 8 (Eight) orders, 24 (Twenty Four) families, and 53 (Fifty-Three) genera. Cypriniformesdominate the whole river and are found in higher numbers and Beloniformes and Tetradontiformes are found in fewer numbers. Species richness in a region is governed by a number of factors that operate at different spatial and temporal scalesviz., speciation, dispersal, competition, disturbance, predation etc.Biotic as well as abiotic factors act together in regulating the local species richness.Stream fishes have been used extensively to examine the relative influences of local and regional factors on local species diversity.Regional diversity is said to be more influenced by biogeography processes.

Key words : Fish Diversity, Freshwater, River Siang, Species, Richness, Arunachal Pradesh.

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