The introduced Southern Bay scallop Argopecten irradians concentricus is one of the most economically important aquaculture species along the southern coast of China.From 2004, mass selections for fast growth in shell height were successively conducted for three generations.Divergence selection for abductor muscle weight was conducted in the offspring stock of F3 selected line (FS), and response to selection and genetic parameters were estimated in the present study.The 10% individuals with largest shell height were first selected from the FS stock, and then, the 30% individuals with heaviest abductor muscle weight and the 30% individuals with lightest abductor muscle weight were selected as the parents of the heavy-selected line (HL) and the light-selected line (LL), respectively.