Comparative study of WLR of Channa striatus of fry-fingerling, growouts and adults of Gangetic plains

Abstract

In the present study the Weight – Length relationships (WLR) are described for the three stages of life of the Snakehead, Saul, Channa striatus, collected from the districts of Barabanki, Lucknow and Unnao in Uttar Pradesh in 2008-09. Method used for analysis of fisheries data on the WLR is (W=aLb) and this study reports the parameters ‘a’ and ‘b’ of the length–weight relationships for one hundred numbers of fry/ fingerlings, thirty-seven grow-out fishes and eighty-nine number of adult fishes collected from the same geographical area. The weight and total length of fry/ fingerlings ranged from 340 to 650 mg and 35 to 45 mm respectively (a=W/L3, 0.0060 to 0.0088; log W=log a + b*(log L), 3.92821 to 4.72919; b=(log W-log a)/log L, 3.89643 to 4.11143). The recorded weight and total length of the grow-outs ranged between 9 to 93g and 10.9 to 25.4 cm respectively (a=W/L3, 0.0082 to 0.0146; log W=log a + b*(log L), 0.95424 to 1.96848; b= (log W-log a)/log L, 3.0). In case of adults the weight and total length recorded ranged between 74 to 476g and 22.9 to 42.4 cm respectively (a=W/L3, 0.0054 to 0.0121; log W=log a + b*(log L), 2.39029 to 4.17039; b=(log W-log a)/log L, 3.40747 to 3.95845). Since fishes were collected during the months of April - May, 2008 and November, 2009, the parameters estimated in this study are considered only for these seasons, because WLR are not constant over the entire year and vary according to factors such as temperature, food availability, feeding rate, gonadal development and spawning period. The result suggests that these fishes grow in a pattern from early life stage to adult if grown in the same environmental conditions.