National Institute of Water and Atmospheric Research, Wellington, New Zealand.
Conservation of Antarctic Marine Living Resources (CCAMLR), Hobart, Australia.
Sci Rep. 2024 Nov 4;14(1):26715. doi: 10.1038/s41598-024-78248-y.
Antarctic toothfish (Dissostichus mawsoni) in the Ross Sea region are believed to spawn predominantly in the northern parts of the Ross Gyre during the austral winter with fluctuations in their recruitment observed. This Lagrangian modelling study attempts to explain these fluctuations and shows how sea-ice drift impacts the buoyant eggs and the overall recruitment of juveniles reaching the Amundsen shelf break. Interannual variations in the Amundsen Sea Low, linked to tropical sea surface temperatures, cause modulations in the sea-ice drift and subsequent recruitment. When the Amundsen Sea Low is weaker, consistent with El Niño conditions, the northward sea-ice drift reduces, and more eggs remain within the Ross Gyre leading to a larger recruitment success. Conversely, recruitment success reduces during La Niña conditions. The sea-ice drift may explain about 80% of the interannual Antarctic toothfish recruitment variability over the period 1975-2016 and is of particular importance during the first year after spawning. These results enable future interannual changes in Antarctic toothfish recruitment success based on remote observations to be anticipated. Our findings suggest that ongoing climate change strengthening of the Amundsen Sea Low, will likely contribute to a long-term toothfish recruitment decline in the Ross Gyre region.
罗斯海海域的南极犬牙鱼（Dissostichus mawsoni）据信主要在南极冬季的罗斯环流北部产卵，其补充群体存在波动。本拉格朗日模拟研究试图解释这些波动，并展示海冰漂流如何影响浮性卵以及到达阿蒙森陆架断裂带的幼鱼的总体补充量。与热带海表温度相关的阿蒙森海低值区的年际变化导致海冰漂流和随后的补充量发生调制。当阿蒙森海低值区较弱时，与厄尔尼诺条件一致，向北的海冰漂流减少，更多的卵留在罗斯环流内，导致更大的补充成功。相反，在拉尼娜条件下，补充成功会减少。海冰漂流可以解释 1975 年至 2016 年期间南极犬牙鱼补充群体 80%左右的年际变化，在产卵后的第一年尤为重要。这些结果可以根据远程观测预测未来南极犬牙鱼补充群体成功的年际变化。我们的研究结果表明，正在发生的气候变化导致阿蒙森海低值区增强，可能会导致罗斯环流区域南极犬牙鱼的长期补充群体下降。
