The two feeding trials were conducted at the Marine Science Institute,Jeju National University, Jeju, South Korea. The fish in genetically homogenous stock were obtained from a private hatchery, Jeju Island,and fed a commercial diet for two weeks to be acclimated to the experimental conditions and facilities. The health status of the fish was checked upon arrival and the fish were immediately treated with 100 mg L−1 formalin for 20 min. Experimental protocols followed the
guidelines of the Animal Care and Use Committee of Jeju National University.