Large aggregations of the copepod Calanus finmarchicus occur each spring in the shelf-slope-oceanic regions off the Lofoten-Vesterålen Islands where productive fisheries have traditionally supported local economies. The retention and off-shelf transport of populations of C. finmarchicus populations were studied by analyzing ocean color remote sensing, satellite altimetry data, and Lagrangian Coherent Structures (LCS) between 2010 and 2019. Our analysis revealed the existence of a transport barrier reoccurring at the shelf break that retains C. finmarchicus on the shelf for 30–70 days in the spring when C. finmarchicus were seasonally ascending to the surface layer. The analysis of baroclinic and barotropic energy conversions indicated that the topographically steered Norwegian Atlantic Current is the primary mechanism in the formation of the transport barrier, which restricts exchanges of C. finmarchicus populations between shelf and oceanic waters. In the mid- to late April, an increase in baroclinicity leads to an increase in mesoscale eddies generated on the shelf break near Lofoten-Vesterålen Islands, breaking down transport barriers and causing off-shelf transport of C. finmarchicus. The transport barrier predictably reoccurs in early spring which supports the entrapment of C. finmarchicus in the shelf region.

中文翻译：

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早春罗弗敦大陆架上的运输障碍和Calanus finmarchicus的滞留

每年春天，在罗弗敦-韦斯特罗伦群岛附近的陆架坡-海洋地区都会出现大量桡足类Calanus finmarchicus，那里的渔业传统上支持当地经济。通过分析 2010 年至 2019 年间的海洋颜色遥感、卫星测高数据和拉格朗日相干结构 (LCS)，研究了C. finmarchicus种群的保留和货架外运输。我们的分析揭示了运输障碍的存在保持所述搁板断裂C. finmarchicus在货架上为30-70天在弹簧时C. finmarchicus季节性上升到表层。对斜压和正压能量转换的分析表明，受地形控制的挪威大西洋洋流是形成运输屏障的主要机制，这限制了C. finmarchicus种群在陆架和海洋水域之间的交换。4 月中下旬，斜压增加导致 Lofoten-Vesterålen 群岛附近陆架断裂处产生的中尺度涡流增加，破坏运输障碍，导致C. finmarchicus离架运输。运输障碍可预见地在早春再次出现，这支持在陆架区域捕获C. finmarchicus。