Interannual variations in diet of Japanese jack mackerel (<scp><i>Trachurus japonicus</i></scp>) juveniles in the southwestern Sea of Japan in relation to recent growth rate

Summary

Abstract We examined interannual variations in the diet of Trachurus japonicus juveniles in relation to prey density and recent 5‐day instantaneous growth rate ( IGR ) in the southwestern part of the Sea of Japan (SJ) in late spring during 2011–2013. Habitat temperature of juveniles in 2011 was lower than the other 2 years. In all 3 years, more than 97% of juveniles had food in the stomach. Small juveniles &lt;35‐mm standard length (SL) fed mainly on adult female Paracalanus parvus s.l., the most dominant calanoid copepod in the water column, without a significant interannual difference. In 2011 and 2012, large juveniles ≥35‐mm SL predated heavily upon adult female Calanus sinicus which form a high‐energy food for the juveniles. In contrast, in 2013, the large juveniles preyed on a large n