The feeding ecology of Pacific Bluefin tuna (PBT: Thunnus orientalis) larvae collected from two nursery grounds, namely the Japan Sea and the Nansei area (western North Pacific), was evaluated based on gut content analyses using morphological and metagenetic techniques. The PBT larvae were collected at the surface layer (≥30 m depth) in 2016 and 2017, and 172 and 114 individuals from the Japan Sea and Nansei area, respectively, were analyzed. A generalized additive model applied revealed that the number of prey in the gut increased with growth, in waters above 24 °C and in subsurface (~30 m depth) waters, during daytime. The total dry weights of prey per gut calculated from the size of copepods and cladocerans also increased during daytime and with growth. Both the morphological and metagenetic analyses indicated that the taxonomic composition of gut contents was influenced by the food selectivity of PBT larvae and by zooplankton (prey) availability in the ambient water. Podonidae were positively selected as PBT larvae prey in both areas, and copepodites and adult Corycaeidae and Pontellidae were positively selected in the Nansei area only. A metagenetic approach indicated Calanidae copepods and soft zooplankton such as appendicularians as important preys in both areas. Other copepods were not positively selected using this approach, but Clausocalanidae and Oithonidae were frequently detected in the Japan Sea. This might be related to the higher abundances of these families in the Japan Sea than in the Nansei area. On the other hand, the cladoceran Penilia avirostris and the copepods Echinostomatidae and Oncaeidae were rarely observed in the guts of PBT larvae although were abundant in the water column. Overall, PBT larvae feed abundantly and grow fast in warm and long-day waters rich in Podonidae, Corycaeidae, Pontellidae, and larval copepods, which contributes to their survival and recruitment in the Japan Sea and Nansei area.

太平洋蓝鳍金枪鱼的摄食生态学（PBT：东方金枪鱼））收集了日本海和南塞地区（北太平洋西部）两个育苗场收集的幼虫，并根据它们的形态学和遗传学技术对其肠道含量进行了评估。在2016年和2017年收集了PBT幼虫的表层（深度≥30 m），并分别分析了来自日本海和Nansei地区的172和114个人。应用的通用加性模型显示，白天白天，肠道中的猎物数量随生长而增加，在24°C以上的水域和地下（约30 m深度）水域中。由co足类和锁骨类的大小计算出的每只肠道的总猎物干重在白天以及随着生长而增加。形态学和遗传学分析均表明，肠道内容物的分类学组成受PBT幼虫的食物选择性和环境水中浮游动物（猎物）的利用率影响。在这两个地区，Podonidae都被积极地选作PBT幼虫，而仅在Nansei地区，就正面地选择了pe足类和成年Corycaeidae和Pontellidae。遗传学方法表明，Calanidae C足类和软浮游动物（例如阑尾动物）是这两个地区的重要猎物。使用该方法未对其他co足类动物进行积极选择，但在日本海中经常发现克劳萨科（Clausocalanidae）和蛇科（Oithonidae）。这可能与日本海中这些家庭的丰富度高于南塞地区有关。另一方面，锁骨 遗传学方法表明，Calanidae C足类和浮游动物（如阑尾动物）是这两个地区的重要猎物。使用该方法未对其他co足类动物进行积极选择，但在日本海中经常发现克劳萨科（Clausocalanidae）和蛇科（Oithonidae）。这可能与日本海中这些家庭的丰富度高于南塞地区有关。另一方面，锁骨 遗传学方法表明，Calanidae C足类和软浮游动物（例如阑尾动物）是这两个地区的重要猎物。使用这种方法未对其他co足类动物进行积极选择，但在日本海中经常发现克劳萨科（Clausocalanidae）和蛇科（Oithonidae）。这可能与日本海中这些家庭的丰富度高于南塞地区有关。另一方面，锁骨尽管在水柱中丰富，但在PBT幼虫的肠道中很少见到小叶青霉和the足纲E科和and科。总体而言，PBT幼虫在丰盛的don鱼科，ry科，Pont鱼科和幼虫pe足类的温暖而长日的水域中觅食并快速生长，这有助于它们在日本海和南塞地区的生存和补充。