This marks the beginning of a tuna fishing season that lasts until early July. After a two-week spawning period, the tuna swim northward in shoals.
黑鮪魚產卵期將近兩個禮拜，一直到七月初都是魚汛期，產卵後的魚群陸續往北移動，部分成熟的黑鮪也遷往日本外海產卵，此時，日本的鮪魚季也才開始。