Length-weight relationship was estimated in six species of threadfin breams occurring in the commercial trawl landings at Chennai during the period 2007-2008. The parameters ‘a’ and ‘b’ of the exponential length-weight relationship of the form W = a Lb are presented for either sex of Nemipterus mesoprion, N. japonicus, N. bipunctatus, N. zysron, N. peronii and N. nematophorus. The regression coefficient ‘b’ was found to range between 2.8 in N. nematophorus to 3.1 in N. bipunctatus. The relationship was found to differ significantly between sexes (p < 0.05) in N. mesoprion and N. zysron. The t-test on the b-values for all these species showed that the slopes did not vary significantly (p > 0.05) from the isometric value of 3

Threadfin breams, length-weight relationship, Nemipterus