Bluefin tuna (BFT), highly prized among consumers, accumulate high levels of mercury (Hg) as neurotoxic methylmercury (MeHg). However, how Hg bioaccumulation varies among globally distributed BFT populations is not understood. Here, we show mercury accumulation rates (MARs) in BFT are highest in the Mediterranean Sea and decrease as North Pacific Ocean > Indian Ocean > North Atlantic Ocean. Moreover, MARs increase in proportion to the concentrations of MeHg in regional seawater and zooplankton, linking MeHg accumulation in BFT to MeHg bioavailability at the base of each subbasin's food web. Observed global patterns correspond to levels of Hg in each ocean subbasin; the Mediterranean, North Pacific, and Indian Oceans are subject to geogenic enrichment and anthropogenic contamination, while the North Atlantic Ocean is less so. MAR in BFT as a global pollution index reflects natural and human sources and global thermohaline circulation.

深受消费者喜爱的蓝鳍金枪鱼 (BFT) 积累了高浓度的汞 (Hg) 作为神经毒性甲基汞 (MeHg)。然而，尚不清楚全球分布的 BFT 人群中汞的生物积累如何变化。在这里，我们显示 BFT 中的汞积累率 (MARs) 在地中海最高，并随着北太平洋 > 印度洋 > 北大西洋而降低。此外，MAR 与区域海水和浮游动物中 MeHg 的浓度成比例增加，将 BFT 中 MeHg 的积累与每个子流域食物网底部的 MeHg 生物利用度联系起来。观察到的全球模式对应于每个海洋亚流域的汞水平；地中海、北太平洋和印度洋受到地质富集和人为污染的影响，而北大西洋则较少。