Farmed salmon may not be as nutritious as it once was, new research suggests
Farmed salmon may not be as nutritious as it once was, new research suggests
最新研究表明：养殖鲑鱼的营养价值可能已大不如前
Eat more fatty fish. That dietary advice has changed the way the world consumes salmon, pushing consumer demand ever upward and production to higher and higher levels. Most of that demand is being met with farmed salmon: Today, nearly 70 percent of the salmon consumed on the planet are raised in pens and cages. 多吃肥鱼。这一饮食建议改变了全球消费鲑鱼的方式，推动消费者需求不断攀升，产量也随之水涨船高。目前，大部分需求由养殖鲑鱼满足：如今，全球近 70% 的鲑鱼是在围栏和网箱中养殖的。
The US Department of Agriculture’s Dietary Guidelines for Americans recommend eating at least 8 ounces of fish a week and urges people to choose salmon or other species that are similarly high in “heart-healthy” Omega-3 fatty acids. But new research led by USDA scientists finds that levels of these fatty acids in farmed salmon have dropped considerably, potentially making the agency’s own advice, and similar recommendations, including from the American Heart Association, outdated and insufficient. 美国农业部的《美国人膳食指南》建议每周至少食用 8 盎司鱼类，并敦促人们选择鲑鱼或其他富含“有益心脏健康”的 Omega-3 脂肪酸的鱼类。但由美国农业部科学家领导的一项新研究发现，养殖鲑鱼中这些脂肪酸的含量已大幅下降，这可能导致该机构自身的建议以及包括美国心脏协会在内的类似建议变得过时且不足。
“These old figures are what are still used in their national dietary guidance,” said Laura Lee Cascada, director of the Aquaculture Accountability Project, a watchdog group. “So in the meantime, it’s going to stay the same and people will have this wrong idea of how much Omegas they’re getting.” “这些旧数据仍被用于国家膳食指南中，”监督组织“水产养殖问责项目”（Aquaculture Accountability Project）主任劳拉·李·卡斯卡达（Laura Lee Cascada）表示，“因此，在短期内，情况不会改变，人们对于自己摄入的 Omega-3 含量仍会有错误的认知。”
The report’s authors note in their research that the sample they examined was not large enough to require changing the government’s advice and that “a broader and more representative study is warranted.” The agency declined requests for an interview and did not answer questions via email. 该报告的作者在研究中指出，他们检查的样本量不足以要求政府改变建议，并表示“有必要进行更广泛、更具代表性的研究”。美国农业部拒绝了采访请求，也未通过电子邮件回答相关问题。
The reason for the decline of the Omega-3s, the new study says, is a major shift in the diets of the naturally carnivorous salmon, from smaller fish species—which were over-exploited to feed farmed fish—to a mix that includes land-based oils and crops, including soy and canola. A 2016 study noted similar declines, also attributable to the shift toward a crop-intensive diet. 新研究称，Omega-3 含量下降的原因是天生肉食性的鲑鱼饮食发生了重大转变：从过去过度捕捞小型鱼类作为饲料，转变为包含陆生油脂和农作物（如大豆和油菜籽）的混合饲料。2016 年的一项研究也注意到了类似的下降，同样归因于向作物密集型饮食的转变。
So, as the well-intended dietary advice has driven a surge in farmed salmon consumption, the corresponding surge in production appears to be depleting the very nutritional benefits that prompted the global salmon boom in the first place—and with consequences for both the marine and terrestrial environment. 因此，虽然出于好意的饮食建议推动了养殖鲑鱼消费的激增，但随之而来的产量激增似乎正在消耗掉当初引发全球鲑鱼热潮的营养价值，并对海洋和陆地环境造成了影响。
Salmon has played a key role in the explosive growth of global aquaculture, becoming a mainstay in the diets of health-conscious eaters or those trying to cut down on terrestrially farmed protein, especially beef, for both health and environmental reasons. The amount of farmed salmon tripled between 2000 and 2020, far outpacing the production of any other type of finned fish. 鲑鱼在全球水产养殖的爆发式增长中发挥了关键作用，成为注重健康的人群或出于健康和环境原因试图减少陆地养殖蛋白质（尤其是牛肉）摄入的人群的饮食支柱。2000 年至 2020 年间，养殖鲑鱼的数量增加了两倍，远远超过了任何其他鳍鱼类的产量。
Today aquaculture is the fastest-growing food production system in the world, much of it spurred by increasing appetites for species, including salmon, that have been identified and marketed as uniquely healthful. But researchers and advocates have long criticized the environmental impacts of farmed salmon. Fish waste and feed pollute waters, threatening wild-caught salmon populations. Feeding ever-greater populations of pen-raised salmon has led to the degradation of both smaller fish species and the coastal fishing communities that depend on them and other wildlife, including seabirds. 如今，水产养殖是世界上增长最快的食品生产系统，很大程度上是由人们对鲑鱼等被认定并营销为“独特健康”的物种的需求增加所推动的。但研究人员和倡导者长期以来一直批评养殖鲑鱼对环境的影响。鱼类排泄物和饲料污染了水域，威胁到野生鲑鱼种群。为了喂养数量日益庞大的网箱养殖鲑鱼，导致了小型鱼类物种的退化，也影响了依赖这些鱼类的沿海渔业社区以及包括海鸟在内的其他野生动物。
With the world’s oceans becoming increasingly depleted of small fish, the industry has switched to feeding salmon a diet based more on terrestrially grown crops, including soy and soy oils. That shift has come with a new set of problems. Most of the world’s soy, roughly 50 percent, is grown in South America where rainforests and other climatically important ecosystems are being razed to grow feed for livestock and aquaculture. 随着世界海洋中的小型鱼类日益枯竭，该行业已转向以陆生作物（包括大豆和豆油）为主的鲑鱼饲料。这种转变带来了一系列新问题。世界上大部分大豆（约 50%）种植在南美洲，那里的雨林和其他对气候至关重要的生态系统正被夷为平地，以种植牲畜和水产养殖饲料。
“Soy is a major, important protein and oil ingredient in fish farming,” said Matthew Hayek, a researcher at New York University who studies the environmental impacts of protein production. “What we can tell is that, for all fish farming combined, soy consumption over the past two decades has amounted to the additional expansion and clearing of forested land that was equivalent to about the size of Nicaragua or Bangladesh.” “大豆是鱼类养殖中一种主要且重要的蛋白质和油脂成分，”纽约大学研究蛋白质生产环境影响的研究员马修·海耶克（Matthew Hayek）说，“我们可以确定的是，在过去二十年中，所有鱼类养殖业的大豆消耗量所导致的森林砍伐和土地扩张，相当于尼加拉瓜或孟加拉国的国土面积。”
Hayek noted that it’s difficult to attribute soy consumption to individual fish species. But other research has found a rise in the use of crop-based ingredients fed to farmed salmon. In Norway, the world’s biggest producer of farmed salmon, 90 percent of feed ingredients were marine-based in 1990, but by 2020 that had dropped to about 23 percent. Advocacy groups there determined that 90 percent of the soy fed to farmed salmon in Norway comes from three Brazilian companies, each of which have sourced soy ingredients from illegally deforested patches of the Amazon rainforest. 海耶克指出，很难将大豆消耗量具体归因于单一鱼类。但其他研究发现，养殖鲑鱼所使用的作物类饲料成分有所增加。在世界最大的养殖鲑鱼生产国挪威，1990 年 90% 的饲料成分来自海洋，但到 2020 年，这一比例已降至约 23%。当地倡导组织确定，挪威养殖鲑鱼所用大豆的 90% 来自三家巴西公司，而这三家公司均从亚马逊雨林非法砍伐的区域采购大豆原料。
Other research has found that the shift to crop-based ingredients doubled the greenhouse gas emissions, per kilogram, of farmed fish in Europe and the United Kingdom from 2000 to 2020. “It’s trading one problem—marine exploitation—for another—land exploitation,” Cascada said. 其他研究发现，从 2000 年到 2020 年，向作物类饲料的转变使欧洲和英国养殖鱼类的每公斤温室气体排放量翻了一番。“这是一种用一个问题（海洋开发）去交换另一个问题（土地开发）的做法，”卡斯卡达说。
The industry is projected to continue growing, along with the population and rising demand for seafood promoted as healthy. Nutritionists and researchers say that farmed fish, including salmon, will play a major role in providing protein, though some environmental groups note the surge in salmon demand has disproportionately come from wealthy countries that don’t have nutritional deficits. 预计该行业将继续增长，人口的增加和对被宣传为“健康”的海鲜的需求也在上升。营养学家和研究人员表示，包括鲑鱼在内的养殖鱼类将在提供蛋白质方面发挥重要作用，尽管一些环保组织指出，鲑鱼需求的激增不成比例地来自并不存在营养匮乏的富裕国家。
“The claim is that the salmon industry is here to feed the world and provide this extra protein,” Cascada said. “But what it’s really doing is flooding the Global North with protein that is not necessarily needed at the expense of the Global South.” “鲑鱼行业的说法是，他们旨在养活世界并提供额外的蛋白质，”卡斯卡达说，“但实际上，他们是以牺牲全球南方为代价，向全球北方倾销并不一定需要的蛋白质。”
In the United States, lawmakers are trying to help the industry expand by passing legislation that would make it easier for salmon producers to obtain licenses to farm fish in offshore federal waters. In February, environmental advocates and fishermen sent a letter to members of Congress opposing the bill, the Marine Aquaculture Research for America (MARA) Act. Proponents of the bill say that putting fish farms in deeper, offshore wa 在美国，立法者正试图通过立法帮助该行业扩张，使鲑鱼生产商更容易获得在联邦离岸水域养殖鱼类的许可。今年 2 月，环保倡导者和渔民致信国会议员，反对这项名为《美国海洋水产养殖研究法案》（MARA Act）的法案。该法案的支持者表示，将养殖场设在更深、更远的离岸水域……