Condition factor and health inference of garua bachcha Clupisoma garua in the river Old Brahmaputra, north-eastern Bangladesh

A twelve-month study over a year was conducted from Januaryto December 2016 to determine condition factor and health condition of garua bachcha, Clupisoma garua (Hamilton, 1822) in the river Old Brahmaputra, Bangladesh.Condition factor of an individual fish was estimated as the ratio of the parameter, a in length-weight relationship (LWR), (W=aLb), and a' in a'=W/Lb, where, L and W are length and weight of the individual fish respectively.  The study calculated condition factors in four ways. Firstly,it was determined according to length classes of each month with corresponding monthly LWR, secondly, according to length classes of each month with LWR of pooled data over the study period. The third and final ways wereemployed according to length classes with LWR of pooled data over the study period, and according to monthly mean length and mean weight data with LWR of pooled data over the study period respectively. Garua bachcha were not in ideal health condition irrespective of length classes and months under any of above mentioned methods of calculation, rather they were either lean or plump during study period. Monthly health conditions did not reveal any definite trend.Monthly sample-wise a'/a values explained that fish individuals were lean in January, while they attained plump health in other months from February to December.