Three specimens of larvae (5.2~7.8 mm in standard length (SL)), of the family Scombridae, were collected from the southeastern waters off Jeju Island in August, 2014. These specimens were identified to Katsuwonus pelamis have melanophores distributed on the 1st dorsal-fin spines and post ventral margin on caudal peduncle. An analysis of the cytochrome oxidase submit I (COI) sequences (652 base pairs) of mitochondrial DNA showed that our specimens must be K. pelamis, because their sequences were concordant with those of the adult K. pelamis (genetic distance= 0.000~0.002), followed by Auxis rochei (genetic distance= 0.061~0.063) and Euthynnus affinis (genetic distance= 0.077~0.079). During the larval stage, K. pelamis differed from Thunnus spp. species in melanophores distribution period of 1st dorsal-fin spines, lower jaws and ventral margin on caudal peduncle. In conclusion, occurrence of K. pelamis larvae means Korean waters are potential spawning ground of K. pelamis.

• 윤상철(국립수산과학원 자원관리과) | Sang Chul YOON (Fisheries Resources Management Division, National Fisheries Research and Development Institute, Busan, 619-705, Korea)
• 정연규(국립수산과학원 자원관리과) | Yeon Kyu JEONG (Fisheries Resources Management Division, National Fisheries Research and Development Institute, Busan, 619-705, Korea)
• 지환성(국립수산과학원 자원관리과) | Hwan Sung JI (Fisheries Resources Management Division, National Fisheries Research and Development Institute, Busan, 619-705, Korea) Corresponding author
• 신아리(국립수산과학원 자원관리과) | Ari SHIN (Fisheries Resources Management Division, National Fisheries Research and Development Institute, Busan, 619-705, Korea)
• 김장근(국립수산과학원 자원관리과) | Zang Geun KIM (Fisheries Resources Management Division, National Fisheries Research and Development Institute, Busan, 619-705, Korea)
• 최광호(국립수산과학원 자원관리과) | Kwang Ho CHOI (Fisheries Resources Management Division, National Fisheries Research and Development Institute, Busan, 619-705, Korea)