In the waters of Tsushima Island, young of dogtooth tuna, Gymnosarda unicolor (Riippell) which were gathered underneath the lurelamp were captured by squid fishing boats on 25 th July, 1970.Since then, the young were caught by surface trolling and set net, and the capture continued to early January 1971.Their size increased as season went on: 24.0-27.5 cm in fork length and 200-300g in body weight in early August;36.0-39.5cm in fork length and 640-910g in body weight in late November;41.0-45.0cm in fork length and 1115-1170g in body weight in the middle of January.But they have not been caught since January of: 1971.
This species had been unknown among the fishermen working around Tsushima Island. This region is outside of their distribution area previously informed by some authors. Therefore, it is highly probable that the occurrence of this species is recorded in the first time here.