Starting ~2010, declines in Calanus finmarchicus and Calanus hyperboreus, the biomass dominant copepods on the northwest Atlantic shelf, coincide with notable ocean warming and a northward shift in endangered North Atlantic right whale (Eubalena glacialis) foraging habitat from the Bay of Fundy/Western Scotian Shelf to the southern Gulf of St. Lawrence (sGSL). Abundance changes in right whales’ prey, lipid-rich Calanus late stages, are known to relate to shifts in Calanus demography and changes in Calanus transport. Our objective was to investigate how these mechanistic drivers shaped potential whale preyscapes during the relatively cooler, high-abundance 2000′s vs the warmer, lower abundance 2010′s. Here, bio-physical Calanus model “Cool Year” and “Warm Year” simulations are used to quantify relative effects of the physical environment vs population level. Analysis is focused on the western sGSL, where right whales have recently been observed foraging in high numbers. Simulations indicate that Calanus variability is most strongly influenced by changes in advection from upstream areas, linked to river runoff and winds on the coastal Gaspé Current in late spring and summer. In the simulated Cool Year (2008), high runoff is associated with a strong Gaspé Current hugging the coastline and advection of Calanus into the western sGSL. Conversely, in the simulated Warm Year (2012), lower runoff led to a separation of the Gaspé Current from the coast, transporting Calanus eastward along the Laurentian Channel, away from Shediac Valley. Variation in population size drives changes in late stage Calanus delivery to the western sGSL in late summer and fall. Complementary analyses on the Western Scotian Shelf indicate that the source of Calanus to Roseway Basin can shift between the coastal Nova Scotia Current and Scotian Shelf slope water, but large declines in upstream population drive lower Warm Year abundance. Our findings inform marine managers about how Calanus high abundance areas may continue to change in the future.

从 2010 年开始，大西洋西北部陆架上生物量占优势的桡足类Calanus finmarchicus和Calanus hyperboreus 数量下降，同时伴随着显着的海洋变暖和濒临灭绝的北大西洋露脊鲸（Eubalena glacialis）从芬迪湾/西部觅食栖息地的北移Scotian Shelf 到圣劳伦斯湾南部 (sGSL)。在露脊鲸猎物丰度的改变，富含脂质的中华哲后期，已知涉及轮班哲人口和改变哲运输。我们的目标是调查这些机械驱动因素如何在相对凉爽、丰度高的 2000 年与温暖、丰度较低的 2010 年期间塑造潜在的鲸鱼猎物景观。在这里，生物物理Calanus模型“冷年”和“暖年”模拟用于量化物理环境与人口水平的相对影响。分析集中在西部 sGSL，最近观察到露脊鲸在那里大量觅食。模拟表明，Calanus上游地区的平流变化对变异性的影响最大，这与春末和夏季沿海加斯佩海流的河流径流和风有关。在模拟的凉爽年（2008 年）中，高径流与强大的加斯佩洋流环绕海岸线和Calanus平流进入西部 sGSL 相关。相反，在模拟的暖年（2012 年）中，较低的径流导致加斯佩海流与海岸分离，将Calanus沿劳伦海峡向东输送，远离希迪亚克山谷。种群规模的变化驱动了晚夏和秋末向西 sGSL 交付的晚期Calanus 的变化。对西斯科舍大陆架的补充分析表明，Calanus的来源到 Roseway 盆地可以在沿海新斯科舍海流和斯科舍大陆架斜坡水之间转移，但上游人口的大幅下降会导致暖年丰度降低。我们的发现让海洋管理者了解Calanus高丰度区域在未来可能会如何继续变化。