Climate-change associated changes in oceanographic conditions, particularly sea surface temperatures (SSTs), have systematically affected many marine fisheries resources around Japan. The Pacific Decadal Oscillation (PDO) index is considered one of the most important climate indices for describing basin-scale SST variations in the North Pacific, which are closely related to decadal variations in fisheries resources. Time series of the PDO index has been used to conventionally classify decadal conditions of ocean and fisheries resources around Japan as either warming or cooling regimes. It is now clear that for the 2000s to the mid-2010s, mostly during the “global surface warming slowdown,” the SST regime around Japan was unconventional; despite the PDO index being in a negative phase, which normally corresponds to a warming regime around Japan, SSTs exhibited decadal cooling in some waters and seasons. SSTs in the western part of the North Pacific subtropical gyre gradually decreased, particularly in autumn–spring, whereas SSTs in the western subarctic gyre and the Sea of Okhotsk increased. Moreover, SSTs between the subtropical and subarctic waters around northern Japan exhibited seasonal contrasts that were decadally intensified through the combined effects of cooling in winter–spring and warming in summer–autumn. Some major marine fisheries resources around Japan showed decadal increases or decreases beginning in the mid-2000s, and appeared to respond to the unconventional SST changes in their early life stages. In this paper, we review atmosphere and ocean conditions around Japan in the 2000s–2010s in terms of global climate, present an overview of potential impacts of decadal SST trends on five major commercial fisheries resources (walleye pollock, chum salmon, Japanese sardine, Japanese anchovy, and Japanese flying squid), and raise awareness that an unconventional regime can appear transiently during a state of global warming.

中文翻译：

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2000-2010 年代日本周边非常规海面温度变化：对主要渔业资源的潜在影响

与气候变化相关的海洋条件变化，特别是海面温度 (SST)，系统地影响了日本周围的许多海洋渔业资源。太平洋年代际振荡（PDO）指数被认为是描述北太平洋流域尺度海温变化最重要的气候指数之一，与渔业资源的年代际变化密切相关。PDO 指数的时间序列通常用于将日本周围海洋和渔业资源的年代际状况分类为变暖或变冷状态。现在很明显，在 2000 年代到 2010 年代中期，主要是在“全球地表变暖放缓”期间，日本周围的海温制度是非常规的；尽管 PDO 指数处于负阶段，这通常对应于日本周围的变暖状况，SSTs 在某些水域和季节表现出十年变冷。北太平洋副热带环流西部海温逐渐降低，尤其是秋春季节，而西亚北极环流和鄂霍次克海海温升高。此外，日本北部亚热带和亚北极水域之间的海温表现出季节性对比，通过冬春季节降温和夏秋季节变暖的综合影响，这种差异在十年间加剧。日本周边的一些主要海洋渔业资源从 2000 年代中期开始出现了年代际增加或减少的情况，并且似乎在其生命早期阶段对非常规的海温变化做出了反应。在本文中，我们从全球气候角度回顾了 2000 至 2010 年代日本周围的大气和海洋状况，