The diet composition of juvenile Trachurus japonicus were studied using 195 specimens collected from 2013 (May, June, July, and September) to 2014 (May, June, and July) in the coastal waters of Geumodo, Yeosu, Korea. The size of juvenile T. japonicus ranged from 4.3 to 15.2 cm in body length (BL). Juvenile T. japonicus was carnivorous and crustaceans predators that consumes mainly consumed copepods. Its diet also included small quantities of decapods, cirripedians, nematods, chaetognathans, fishes, amphipods, cumaceans, ostracods and euphausiids. The graphical method for feeding strategy revealed that juvenile T. japonicus is an opportunistic and specialized predator on copepods, especially Corycaeus. affinis, and showed narrow niche width. Juvenile T. japonicus showed ontogenetic diet change. Small size group individuals (4.3–8.0 cm BL) mainly consumed copepods. The portion of this prey item decreased in the large size group (8.0–15.2 cm BL), and this decrease was paralleled with increased consumption of decapods.

• 김희용 | Heeyong KIM
• 임유나(국립수산과학원 연구기획과) | Yu Na LIM (Research and Development Planning Division, National Fisheries Research & Development Institute, Busan, 619–705, Korea)
• 정재묵(국립수산과학원 연구기획과) | Jae Mook JEONG (Research and Development Planning Division, National Fisheries Research & Development Institute, Busan, 619–705, Korea)
• 김현지(국립수산과학원 연구기획과) | Hyeon Ji KIM (Research and Development Planning Division, National Fisheries Research & Development Institute, Busan, 619–705, Korea)
• 백근욱(국립수산과학원 연구기획과) | Gun Wook BAECK (Research and Development Planning Division, National Fisheries Research & Development Institute, Busan, 619–705, Korea) Corresponding author