author(s)
Sarbjeet Kaur, Prabjeet Singh and SS Hassan

abstract
A study of seasonal variations in the gonado-somatic index was conducted for selected fish species of river Sutlej in and around Ludhiana. Two different sites i.e. site I (before confluence of Buddah Nallah) and site II (after confluence of Buddah Nallah) were selected for the study. Maximum mean GSI (Female) values (%) were observed during monsoon period whereas minimum mean GSI values were observed during post-monsoon period for Labeo rohita, Wallago attu, Aorichthys seenghala and Notopterus chitala at S-1 and S-2, respectively, except for C. marulius, in which the maximum mean value of GSI was observed during pre-monsoon (June) whereas minimum mean value was observed during monsoon period (July-August) at S-1 and S-2, respectively, because of its only one spawning period (June-July). GSI is the calculation of gonadal mass as a proportion of the total body mass and recognized as specific indicators of maturity and periodicity of fish spawning. The present work was undertaken in order to determine the spawning season of selected commercially important fish species of River Sutlej based on Gonado-somatic index and the outcome is helpful for selective breeding programme, conservation and sustainable fishery management of commercially important fishes in natural water bodies.