Young-of-the-year (0-group) fish in the Barents Sea have been investigated in an annual joint Norwegian-Russian pelagic trawl survey in autumn, using a standardized procedure since 1980. We use a conceptual framework of ‘upstream’ spawning areas and ‘downstream’ nursery areas, recorded as 0-group distribution in the Barents Sea, to address spatial (geographical) and temporal (1980–2017) variation in 0-group length. Four boreal species (cod Gadus morhua, haddock Melanogrammus aeglefinus, herring Clupea harengus, and deepwater redfish Sebastes mentella) tended to have smaller 0-group individuals in the northern and eastern parts of the Barents Sea, with the largest individuals found in the central part where they were also most abundant. We interpret this to reflect slower growth as the ‘fore-runners’ of the seasonal cohort of juveniles are transported into colder waters (through lateral mixing). The Arctic species (capelin Mallotus villosus and polar cod Boreogadus saida) showed a different pattern with increasing 0-group length with increasing distance away from the spawning areas, seen most clearly for capelin. The longer juveniles in northern areas are probably older and stemming from early spawning.

There was temporal covariation in 0-group length between the six species over the 38-year time series, with highest correlation between cod and haddock. The covariation reflected similar fluctuations in four decadal ‘waves’, with maxima in 0-group length in the early/mid 1980s, 1990s, 2000s, and 2010s. There was a high degree of spatial consistency in the temporal patterns of variation in 0-group length, with synchronous variations in different geographical areas. There were also increasing linear trends over the time series for cod, haddock, and polar cod, which represented increase of about 20%, 40%, and 15% of the initial length for the three species, respectively. The fluctuations and trends in 0-group length were positively correlated with seawater temperature, which suggests a strong effect of climate variability and warming (by 1.5–2.0 °C since 1980) on 0-group length. The clear differences among the species, and the limited fraction of variance explained by temperature, suggest that other factors such as food play additional roles. Zooplankton biomass integrated over the water column had low explanatory power, but this may reflect intrinsic limitations in the data (e.g., depth-integrated, end of season) in providing an adequate representation of feeding conditions, rather than suggesting that food was not important.

自 1980 年以来，使用标准化程序，在秋季进行的年度挪威-俄罗斯远洋拖网联合调查中对巴伦支海的幼鱼（0 组）进行了调查。我们使用“上游”产卵的概念框架区域和“下游”苗圃区，记录为巴伦支海的 0 组分布，以解决 0 组长度的空间（地理）和时间（1980-2017）变化。四种北方物种（鳕鱼Gadus morhua、黑线鳕Melanogrammus aeglefinus、鲱鱼Clupea harengus和深水红鱼Sebastes mentella) 倾向于在巴伦支海的北部和东部拥有较小的 0 群个体，最大的个体在中部发现，它们也最丰富。我们将此解释为反映生长缓慢，因为季节性青少年群体的“先行者”被运送到较冷的水域（通过横向混合）。北极物种（毛鳞鱼Mallotus villosus和极地鳕鱼Boreogadus saida）表现出不同的模式，随着距产卵区距离的增加，0 群长度增加，毛鳞鱼最为明显。北部地区较长的幼鱼可能年龄较大，并且源于早期产卵。

在 38 年的时间序列中，六个物种之间的 0 组长度存在时间协变，其中鳕鱼和黑线鳕之间的相关性最高。协变反映了四个年代际“波”中的类似波动，在 1980 年代早期/中期、1990 年代、2000 年代和 2010 年代，0 组长度达到最大值。0组长度变化的时间模式具有高度的空间一致性，在不同的地理区域具有同步变化。鳕鱼、黑线鳕和极地鳕鱼的时间序列也呈线性增加趋势，这三个物种的初始长度分别增加了约 20%、40% 和 15%。0 组长度的波动和趋势与海水温度呈正相关，这表明气候变率和变暖的强烈影响（1.5-2. 0 °C 自 1980 年）在 0 组长度上。物种之间的明显差异，以及由温度解释的有限差异部分，表明食物等其他因素起着额外的作用。整合在水柱上的浮游动物生物量具有较低的解释力，但这可能反映了数据（例如，深度整合，季节结束）在提供摄食条件的充分代表性方面的内在局限性，而不是表明食物并不重要。