Predation can be a significant source of natural mortality for small pelagic fish species, rivaling or exceeding fishery removals. Failure to account for changes in natural mortality can introduce uncertainty in the assessment and management of these stocks. In this study, a 10‐year span of hydroacoustic data was used to detect Bluefin Tuna Thunnus thynnus on two major fall spawning grounds of Atlantic Herring Clupea harengus, an economically and ecologically valuable forage fish species in the southern Gulf of St. Lawrence (sGSL). Average Bluefin Tuna detections increased 22‐fold from 2002 to 2012 on both spawning grounds independently of Atlantic Herring density or aggregation size. This increase is directionally consistent but larger than changes in other Bluefin Tuna population indices. Preliminary estimates of annual Atlantic Herring consumption doubled across the time series, reaching values of 4,300–20,000 metric tons in recent years. This would suggest that Bluefin Tuna are among the most important consumers of Atlantic Herring in the sGSL. These findings are key for an ecosystem‐based approach to the assessment and management of both Atlantic Herring and Bluefin Tuna in the sGSL.

中文翻译：

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在大西洋鲱鱼产卵场上大西洋蓝鳍金枪鱼的发生率增加：上层捕食者与猎物之间相互作用的信号增强了吗？

捕食可能是远洋鱼类小型自然死亡的重要来源，其捕捞量甚至超过或超过捕捞量。如果不考虑自然死亡率的变化，可能会给这些种群的评估和管理带来不确定性。在这项研究中，使用了10年的水声数据跨度，在大西洋鲱鲱Clupea harengus的两个主要秋季产卵场上检测了蓝鳍金枪鱼Thunnus thynnus是位于圣劳伦斯湾（sGSL）南部的具有经济和生态价值的饲料鱼。从2002年到2012年，在两个产卵场中，平均蓝鳍金枪鱼的检测量增加了22倍，而与大西洋鲱鱼的密度或聚集体大小无关。这种增加在方向上是一致的，但大于其他蓝鳍金枪鱼种群指数的变化。在整个时间序列中，对大西洋鲱鱼年消费量的初步估计增加了一倍，近年来达到了4,300–20,000公吨。这表明蓝鳍金枪鱼是sGSL中大西洋鲱鱼最重要的消费者之一。这些发现对于评估和管理sGSL中的大西洋鲱鱼和蓝鳍金枪鱼的基于生态系统的方法至关重要。