The present study determined the differences in the morphometric characteristics of truss and classical dimensions between diploid and triploid Far Eastern catfish, Silurus asotus and provided methods for separating diploid and triploid Far Eastern catfish based on morphometric observations. Significant variables were the direct distance between the anterior edge of the lower lip and the anterior insertion of the dorsal fin (DALAD), the horizontal distance between the anterior edge of the lower lip and the anterior insertion of the ventral fin (HALAV), the direct distance between the anterior edge of the upper lip and the first nostril (DAUF), the direct distance between the anterior edge of the upper lip and the second nostril (DAUS), the interorbital width (IW), and the mandible barbel length (ManBL). The more significant variables were DALAD, HALAV, DAUF, DAUS, and IW. The most useful combination of variables for separating the two groups was DALAD, IW, and DAUF, which correctly classified 85% of the catfish as triploid or diploid, the maximum degree of separation obtained (P<0.05). The triploid catfish had high head region and body depth growth rates during the first year after hatching. Triploid catfish had smaller heads and shorter mandible barbels than diploid catfish.

• In-Seok Park(Division of Marine Environment and Bioscience, College of Ocean Science and Technology, Korea Maritime and Ocean University)
• Hyun Woo Gil(Division of Marine Environment and Bioscience, College of Ocean Science and Technology, Korea Maritime and Ocean University)
• In Bon Goo(Division of Marine Environment and Bioscience, College of Ocean Science and Technology, Korea Maritime and Ocean University)