Instituto Español de Oceanografía, Centre Oceanogràfic de les Balears, Palma, Spain.
Instituto Español de Oceanografía, Centro Oceanográfico de Málaga, Fuengirola, Spain.
J Fish Biol. 2022 Jan;100(1):203-217. doi: 10.1111/jfb.14935. Epub 2021 Nov 15.
Mature albacore tuna (Thunnus alalunga) are expected to have high energy requirements at the time of breeding. However, there are no descriptions of the diet of albacore in the Mediterranean Sea that can help us to understand if such requirements can be obtained from feeding during reproduction. In this study, we analysed the stomach contents of reproductively active albacore captured from 2010 to 2015 in the oligotrophic waters of the western Mediterranean Sea, one of their main spawning grounds. Estimates of stomach fullness revealed intense feeding activity, and prey composition indicated important consumption of mesopelagic fish, including barracudinas, myctophids and small pelagic crustaceans. Plastic debris occurred in 25%-53% of the stomachs sampled across all years. Prey composition was not different between males and females. However, females fed at higher rates and had higher hepatosomatic index values than males, suggesting that increased feeding could contribute to meet their higher energy demand associated with offspring production. We observed a diet shift from small crustaceans to fish prey along fish size. During the spawning period, albacore showed a specialist feeding behaviour by preying on aggregations of vertically migrating myctophids and small crustaceans, probably when they were near the surface. This study provides information and biological data to support ecosystem modelling and to increase the understanding of albacore ecology.
成熟的长鳍金枪鱼（Thunnus alalunga）在繁殖期预计会有很高的能量需求。然而，目前地中海海域长鳍金枪鱼的饮食描述尚不清楚，无法确定它们在繁殖期间的摄食是否能够满足这些需求。本研究分析了 2010 年至 2015 年间在贫营养的地中海西部海域中处于繁殖活跃期的长鳍金枪鱼的胃内容物，该海域是它们的主要产卵场之一。胃饱满度的估计表明其摄食活动强烈，且猎物组成表明其重要的摄食对象包括梭子鱼、深海鱼类和小型浮游甲壳类动物。在所有年份的样本中，有 25%-53%的胃中存在塑料碎片。雌雄个体之间的猎物组成没有差异。然而，雌性的摄食率高于雄性，且具有更高的肝体指数值，这表明增加的摄食可能有助于满足其与后代生产相关的更高的能量需求。我们观察到，随着鱼类体型的增大，其食物组成从小型甲壳类动物转变为鱼类。在繁殖期间，长鳍金枪鱼表现出一种专门的摄食行为，捕食垂直洄游的深海鱼类和小型甲壳类动物的聚集体，可能是在它们接近水面时。本研究提供了信息和生物学数据，以支持生态系统模型的建立，并增加对长鳍金枪鱼生态学的理解。
