Abstract: The selectivity of the fish traps with different mesh sizes for masked greenling Hexagrammos otakii was investigated using logistic curve as a selectivity model and by cover-net method in a laboratory flume to find out the optimal mesh size for fishing.Parameters of selectivity were estimated according to the maximum likelihood method. It was found that the 50%selection length L50of masked greenling was 15.42 cm at mesh size of 5 cm with selectivity facor（SF）of 6.71，18.07 cm at mesh size of 6 cm with SF of 6.02，and 21.68 cm at mesh size of 7 cm with SF of 5.42，indicating that the L50and selectivity range（SR）were increased as increase in mesh size of cage，and that the SF reduced as increase in mesh size of cage.The linear regression equation between（L50）and the mesh size of webbing（m）was expressed as L50=3.127 m-0.372，R2=0.992.It was concluded that suitable size of fishing gear for protecting masked greenling resources was of 6 cm mesh size.
2016, Vol. 31 
