Nature┃气候变化，海产品如何跟上步伐?

可持续地满足不断增长且日益富裕的人口的粮食需求将是二十一世纪的最大挑战之一。而海洋占据了世界近四分之三的表面积，目前却仅提供全球肉类供应的 17%。（近海）海水养殖发展潜力巨大，但海水养殖的真正未来取决于人类对气候变化的反应，即渔业和海水养殖的协调改革是否能在气候变化下提高人均海鲜产量？

4 Y' {- ]& G' U* K7 A& n Sustainably meeting the growing food demands of  increasingly affluent human will be one of the greatest challenges of the twenty-first century. Despite occupying nearly three-quarters of the world’s surface area, the ocean currently provides only 17% of the global meat supply. Although fisheries reforms and advances in offshore aquaculture (hereafter “mariculture”) could increase production, the true future of seafood depends on human responses to climate change, which means that whether coordinated reforms in fisheries and mariculture could increase seafood production per capita under climate change.
2022 年 4 月 27 日，来自美国加利福尼亚大学、澳大利亚詹姆斯·库克大学、菲律宾大学等科研机构的的 14 位研究人员在《Nature》上在线发表了一篇名为“Expanding ocean food production under climate change”的研究论文，文章的中文译名是《在气候变化下扩大海洋粮食生产》。
On April 27, 2022, 14 researchers from scientific research institutes like University of California, James Cook University and University of the Philippines Diliman published a paper online entitled “Expanding ocean food production under climate change” in Nature.

                               
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海洋渔业的生产力以及适合海水养殖的区域范围预计随着海洋气候条件的变化而下降，人类的积极行动至关重要。对此，文章的主要作者 Christopher M. Free 研究了适应性渔业改革是否有助于应对本世纪迫在眉睫的粮食安全挑战。

Both the productivity of marine fisheries and extent of suitable area for mariculture are expected to decline as ocean conditions change, so the human responses are very important. Here Christopher M. Free and other research fellows investigated whether climate adaptive actions in both ocean food sectors collectively could help to meet the looming food security challenges of this century.

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3 `: h  D3 a) { 图 1 显示，除最严重的温室气体排放情况外，所有情况下人均海产产量都可能增加，但人口增长意味着这些增长不太可能足以在任何气候变化情景下维持人均海产品产量，不过它们产生的效果已经远远好于一切照旧的管理。预计大多数国家的人均海产品量将少于现今水平，而在面临渔业生产力下降幅度最大、人口增长最快的热带低收入国家，预计人均海产品供应损失将特别大。因此，气候适应性渔业改革对于最大限度地减少留给国内海水养殖或国际贸易的海产品短缺，并最大限度地提高捕捞渔业的生计和文化价值非常重要。
  m2 v/ P. d( G, h' d7 O Although fisheries reforms could increase global seafood production under all but the most severe climate scenario (Fig. 1a), a growing human population means that these increases are unlikely to be sufficient for maintaining per capita seafood production under any climate-change scenario. But the results are better than those of business-as-usual management. Most countries are projected to have less seafood per capita than today. Losses in per capita seafood supply are projected to be especially large in tropical low-income countries that face the largest declines in fisheries productivity and the greatest human population growth. Climate-adaptive fisheries reforms are therefore important to minimize the seafood deficit left for domestic mariculture or international trade to fill and to maximize the livelihood and cultural value of capture fisheries.

                               
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图 2 显示，虽然过去海水养殖生产也受到气候变化的挑战，但它发展迅速，近 30 年来，海水养殖种类数量增加了 30%，这些增长取决于渔业改革、饲料技术的持续进步以及建立有效的海水养殖管理和最佳做法。如果不受未来消费者需求上限（虚线）或捕捞渔业饲料供应（点）   的限制。未来消费者需求的上限估计是之前估计的 2050 年需求的两倍。此外，大幅减少排气候变化对于减少不平等、提高改革效率和减少分析中未考虑的风险至关重要。
  ?- ^4 p) V& A+ ?. P7 B Although mariculture production is also challenged by historical climate change, it has grown rapidly. Over the past three decades, the number of mariculture species has increased by 30%, which is the result of fisheries reforms, innovations in feed and effective  breeding for fast growth. If unconstrained by the upper limits of future consumer demand (dotted lines) or the availability of feed from capture fisheries (dots), the upper limits of future consumer demand were estimated to be double the 2050 demand estimated previously. Furthermore, dramatically curbing emissions is essential for reducing inequities, increasing reform efficacy and mitigating risks unaccounted for in our analysis.

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图 3 显示，如果不对渔业管理进行改革，也不在饲料海水养殖方面进行技术创新，就不可能实现可持续海水养殖增加人均海产品产量的能力。一切照旧的渔业管理假定，随着种群转移到新的管理区，目前的捕捞率会下降，而改革后的渔业管理假定，随着种群转移到新的管理区，经济上最佳的捕捞率得以维持。渔业管理改革和海水养殖技术的进步可以在除最严重的气候变化情景之外的所有情况下增加全球人均海产品产量

As shown in Fig. 3, the ability for sustainable mariculture to increase seafood production per capita is not possible without both reforms in fisheries management and technological innovations in fed mariculture. Business-as-usual fisheries management assumes that current harvest rates degrade as populations shift into new management areas whereas reformed fisheries management assumes that economically optimal harvest rates are maintained as populations shift into new management areas. As a result, reforms in fisheries management and advances in mariculture technology could increase per capita global seafood production under all but the most severe climate-change scenario.

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为了评估沿海国家通过改革渔业和扩大可持续海水养殖来避免国内海产品短缺的能力，图 4 模拟了四种发展情景，发现在大多数沿海国家，避免国内海产品短缺也许是可能的，但将取决于哪些国家优先考虑对渔业改革和可持续海水养殖扩张的投资。
To assess the ability of coastal countries to avoid domestic seafood deficits by reforming fisheries and expanding sustainable mariculture, the authors modelled four development scenarios. And they find that avoiding domestic seafood deficits may be possible in most coastal countries, but will depend on which countries prioritize investment in fisheries reforms and sustainable mariculture expansion.
* O( _, z2 k3 Y+ Q) f7 ?. e综上，研究人员认为：尽管气候变化将挑战海洋满足日益增长的粮食需求的能力，但通过迅速而雄心勃勃的行动，减少温室气体排放、改革捕捞渔业和扩大可持续的海水养殖业务，海洋可以生产比目前更多的粮食。扩大可持续海水养殖将需要在更多地方确定和支持可持续海   水养殖发展的政策，重点关注许多渔业被过度捕捞的热带低收入国家，以免加剧现有的社会   经济不平等。
& B. Y  Z3 o/ N$ c  l/ HOverall, the researchers find that although climate change will challenge the ocean’s ability to meet growing food demands, the ocean could produce more food than it does currently through swift and ambitious action to reduce emissions, reform capture fisheries and expand sustainable mariculture operations. Expanding sustainable mariculture will require policies that define and support sustainable mariculture development in more places. Therefore, we should pay attention to many fisheries in tropical low-income countries overfished to avoid economic inequities.

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参考文献：www.52ocean.cn