Length weight relationship of cobia, Rachycentron canadum from hook and line fishery at Gulf of Mannar region, South East Coast of India

Length weight relationship of Rachycentron canadum landed by hook and line fishery in Gulf of Mannar coast during February 2010 to March 2012 was estimated. A total of 330 fishes were examined from hook and line fishery consisting of 130 males and 170 females. Total Length (TL) for males ranged between 53 and 144 cm with a mean length of 98.12 +/- 22.87 cm, and the weight ranged from 1 to 31 kg with a mean of 11.15 +/- 7.73kg. In the case of female the Total length observed was between 43 and 148.1 cm with a mean length of 95.84 +/- 24.11 cm and the weight observed was between 0.25 to 35.2 kg with a mean weight of 10.37 +/- 8.38 kg. This present study suggests that the values of the slope b were 3.12 and 3.36 for male and female cobia respectively which showed positive allometric growth rate (b>3), suggesting that they are fast growing fishes.