PNAS:新发现的金枪鱼产卵地
美国国家海洋大气管理局东北渔业科学中心科研人员报告了一个此前没有被发现的蓝鳍金枪鱼在西大西洋的产卵地。管理大西洋蓝鳍金枪鱼渔业具有挑战性，这是由于大西洋蓝鳍金枪鱼的高度迁徙的生活方式以及捕获这种鱼的国家数量很多。制定有效的管理策略需要理解这个物种的生命史。David Richardson及其同事在2013年6月底到8月初期间收集了来自美国东北部沿海Slope 海的67条蓝鳍金枪鱼稚鱼。在收集到这些稚鱼的时候，它们大部分只有6天大，这表明，除了此前在地中海和墨西哥湾识别出的产卵地，Slope 海是大西洋蓝鳍金枪鱼的产卵地。电子标签数据表明，蓝鳍金枪鱼在西大西洋的迁徙模式随着鱼的尺寸而变化。只有最大的个体迁移到墨西哥湾，而小到中型尺寸的个体在北马尾藻海与美国东北之间迁徙，这提示了很大一部分西大西洋蓝鳍金枪鱼的产卵发生在墨西哥湾之外。这组作者说，西大西洋蓝鳍金枪鱼当前的生命史模型假定产卵仅仅发生在墨西哥湾，这可能高估了成熟的年龄，而西大西洋蓝鳍金枪鱼对于渔业利用的脆弱性可能比此前认为的要低。
原文链接：
Discovery of a new spawning ground reveals diverse migration strategies in Atlantic bluefin tuna (Thunnus thynnus)
原文摘要：
Atlantic bluefin tuna are a symbol of both the conflict between preservationist and utilitarian views of top ocean predators, and the struggle to reach inteRNAtional consensus on the management of migratory species. Currently, Atlantic bluefin tuna are managed as an early-maturing eastern stock, which spawns in the Mediterranean Sea, and a late-maturing western stock, which spawns in the Gulf of Mexico. However, electronic tagging studies show that many bluefin tuna, assumed to be of a mature size, do not visit either spawning ground during the spawning season. Whether these fish are spawning in an alternate location, skip-spawning, or not spawning until an older age affects how vulnerable this species is to anthropogenic stressors including exploitation. We use larval collections to demonstrate a bluefin tuna spawning ground in the Slope Sea, between the Gulf Stream and northeast United States continental shelf. We contend that western Atlantic bluefin tuna have a differential spawning migration, with larger individuals spawning in the Gulf of Mexico, and smaller individuals spawning in the Slope Sea. The current Life history model, which assumes only Gulf of Mexico spawning, overestimates age at maturity for the western stock. Furthermore, individual tuna occupy both the Slope Sea and Mediterranean Sea in separate years, contrary to the prevailing view that individuals exhibit complete spawning-site fidelity. Overall, this complexity of spawning migrations questions whether there is complete independence in the dynamics of eastern and western Atlantic bluefin tuna and leads to lower estimates of the vulnerability of this species to exploitation and other anthropogenic stressors.
作者：David E. Richardson
