Li says the nocturnal bluefin are generally active at depths of 50-60 meters below the sea surface, but in the breeding season, the male fish jump out of the water to court the females. In the daytime the tuna cannot dodge the gaze of predators such as dolphins and whales, so they do their courting by moonlight.
兩次跟著漁船出海的李彥宏說，夜行性的黑鮪魚，平時在海面以下到五、六十公尺水深處活動，繁殖時期，公鮪魚會躍出水面追逐母魚，由於白天難躲海豚、鯨魚等天敵的覬覦，黑鮪魚都在夜晚迎著月光求偶，黑夜的大海因此顯得浪漫詩意。