RESUMEN
This study is based on the length-weight relationships (LWRs) of 2148 fishes, belonging to 8 families, 12 genera and 15 freshwater fish species (Wallago attu, Rite rita, Sperato seenghala, Sperota aor, Mostacembalus armatus, Macrognathus puncolus, Gudusia chopra, Clupisoma garua, Puntius sophore, Puntius ticto, Rasbora daniconius, Amblypharyngodon mole, Chanda noma, Colisa fociatus and Colisa sota) captured from river Ganga, Gomti and Rapti during May 2011 to March 2012. The growth coefficient (b) values varied between 1.30 and 3.07, with the mean b = 2.03 at p< 0.001. The condition factor (K) varied considerably from 0.76 and 2.95, with a mean K = 1.43 which may be attributed to different environmental conditions of the river basin. The objective was to evaluate the pattern of LWRs and condition factors of the freshwater fish species of the main Ganga and tributaries which serves as baseline for other tropical Indian rivers and tributaries.