Length weight relationship and ponderal index of rainbow trout (Oncorhynchus mykiss W., 1792) from Dachigam stream in Kashmir

The rainbow trout (Oncorhynchus mykiss), introduced in Kashmir in 1912, has thrived well since then and is now established in almost all the cold water streams, lakes and rivers of the valley. This study was aimed to describe the length-weight relationship and ponderal index (condition factor) of the fish from Dachigam stream in Kashmir. The investigation was carried out between April and December, 2005 and the data were recorded from anaesthetized fish, which ranged from 110 to 488 mm in length and 20 to 1425 g in weight. The length-weight relationship was estimated as LogW = - 4.9216 + 2.9618LogL and the b value (2.9618) did not differ significantly from 3. The coefficient of correlation (r) for the length-weight relationship was estimated at 0.9968 which showed a high degree of positive correlation between the length and weight of the fish. The condition factor (K) value was estimated as 1.15 ± 0.013.   Key words: Oncorhynchus mykiss, rainbow trout, length weight relationship, ponderal index, Dachigam stream, Kashmir.