Length-weight Relationship of Two Species of Trichogaster (colisa) from Brahmaputra Basin of Assam

Length-weight relationship (LWR) of Trichogaster species belongs to the Belontidae family inhabiting Brahmaputra basin, were studied. The fishes Trichogaster fasciata and T. sota were obtained from fish landing site at different floodplain beels of Brahmaputra basin during 2010 to 2011. The parameters ‘a’ and ‘b’ of the length-weight relationship of the form W = aLb and condition factor (K) = W1000/L 3 are presented for the two fish species. The results reveals that the value of regression coefficient ‘b’ of Trichogaster fasciata, tends to be higher during pre-monsoon and lower during winter while in T. sota, it tends to be higher during winter and lower during post monsoon seasons. The exponential index ‘b’ for female (2.040) was found to be lower than that of male (2.424) in Trichogaster species while male (1.042) was lower than female (1.232) in T. sota. The ‘K’ value was found between 16.87 and 22.19 for T. fasciata, while it was between 19.71 and 33.59 for T. sota. This indicates an allometric relationship in the growth and healthy condition for both the species.