Freshly hatched tuna fry are only three to four millimeters long, and are completely at the mercy of the ocean currents. Hitching a ride on the Kuroshio Current, they drift north, surrounded by hungry predators. Those that survive stop to winter in the waters off Japan.
初生的黑鮪寶寶只有○・三、四公分，在浩瀚澎湃的大海之中，牠們雖缺乏駕馭海流的能力，卻能輕鬆地搭乘黑潮，隨波逐流，往北而去，海中載沈載浮的小魚，必須面對大魚環伺與險惡暗潮，幸運虎口餘生的魚兒，停留在日本海域過冬。