Ocean warming has been affecting marine ecosystems over the past few decades. The signature of ocean warming in global fisheries catch data has been identified through a variety of methods, one of which is the mean temperature of the catch (MTC) index. The MTC is derived from the average temperature preference of fished species weighted by their contribution to annual catches. Here, we used MTC to explore the fisheries catch responses to warming, from 1950 to 2016, along a latitudinal gradient in the western Pacific Ocean, from 37° N, via 2.5° S in the central western Pacific, to 36° S. The tropicalization of catches in a given geographic space, i.e., the increased catch of species with affinity to warmer waters, as a result of increasing sea temperature and the associated poleward migration of species, rather than any large-scale oceanographic variability, was apparent through the increasing MTC at higher latitudes. In particular, MTC in temperate Japan increased by 0.33 °C per decade over the time series. The MTC in subtropical/temperate southeast Australia increased by 0.24 °C per decade over the full time period and by 1.24 °C per decade after 2002. The observed MTC increase was caused by the increasing dominance of thermophilous (preferring warmer waters) over psychrophilous (preferring cooler waters) taxa in the catches in these waters. On the other hand, the MTC in tropical Indonesian waters, as well as the ratio of thermophilous to psychrophilous taxa, showed a gentle yet consistent decrease of 0.05 °C per decade over the full time period. This finding supports the tropicalization hypothesis, given the limited scope for further tropicalization of catches in the already tropical ecosystem of Indonesia. Ocean warming has indeed been altering the distribution of marine organisms, particularly in temperate ecosystems as thermophilous taxa become more abundant, while psychrophilous taxa abundance decreases. Tropicalization impacts fisheries and catch composition and is, therefore, expected to cause conflicts among fishers and challenge fisheries management.

在过去的几十年里，海洋变暖一直在影响海洋生态系统。已通过多种方法确定了全球渔业捕捞数据中海洋变暖的特征，其中之一是捕捞平均温度 (MTC) 指数。MTC 源自捕捞物种的平均温度偏好，按其对年捕捞量的贡献加权。在这里，我们使用 MTC 来探索渔业捕获量对变暖的响应，从 1950 年到 2016 年，沿西太平洋的纬度梯度，从 37° N，经中西太平洋的 2.5° S，到 36° S。特定地理空间内的捕捞量热带化，即由于海水温度升高和相关的物种向极地迁移，对温暖水域有亲和力的物种捕捞量增加，而不是任何大规模的海洋变化，通过在高纬度地区增加的 MTC 是显而易见的。特别是，在时间序列中，日本温带地区的 MTC 每十年增加 0.33 °C。澳大利亚东南部亚热带/温带的 MTC 在整个时期内每十年增加 0.24 °C，在 2002 年之后每十年增加 1.24 °C。更喜欢较凉的水域）在这些水域的渔获物中分类群。另一方面，印度尼西亚热带水域的 MTC 以及嗜热与嗜冷分类群的比率在整个时间段内每十年温和而一致地下降 0.05 °C。这一发现支持了热带化假说，鉴于印度尼西亚已经是热带生态系统的渔获物进一步热带化的空间有限。海洋变暖确实改变了海洋生物的分布，特别是在温带生态系统中，因为嗜热类群变得更加丰富，而嗜冷类群的丰度却在下降。热带化影响渔业和渔获量构成，因此预计会引起渔民之间的冲突并挑战渔业管理。