SI Appendix 1. Dataset supporting Arce et al. doi:10.1098/rspb.2021.2452 from Elephant seal foraging success is enhanced in Antarctic coastal polynyas

Antarctic polynyas are persistent open water areas which enable early and large seasonal phytoplankton blooms. This high primary productivity, boosted by iron supply from coastal glaciers, attracts organisms from all trophic levels to form a rich and diverse community. How the ecological benefit of polynya productivity is translated to the highest trophic levels remains poorly resolved. We studied 119 southern elephant seals feeding over the Antarctic shelf and demonstrated that (i) 96% of seals foraging here used polynyas, with individuals spending on average 62% of their time there, (ii) the seals exhibited more area-restricted search behaviour when in polynyas and (iii) these seals gained more energy (indicated by increased buoyancy from greater fat stores) when inside polynyas. This higher quality foraging existed even when ice was not present in the study area, indicating that these are important and predictable foraging grounds year-round. Despite these energetic advantages from using polynyas, not all the seals used them extensively. Factors other than food supply may influence an individual's choice in their use of feeding grounds, such as exposure to predation or the probability of being able to return to distant sub-Antarctic breeding sites.

南极冰间湖（Antarctic polynyas）是一类持续存在的开阔水域，可催生季节性浮游植物（phytoplankton）的早发大规模水华。这种由沿海冰川补给铁元素所提升的高初级生产力，吸引了各营养级（trophic levels）的生物聚集，形成丰富多样的群落。目前，冰间湖生产力所带来的生态效益如何传递至最高营养级，仍未得到充分阐明。我们对119头在南极陆架（Antarctic shelf）区域觅食的南象海豹（southern elephant seals）展开研究，结果证实：(i) 在此觅食的海豹中有96%会利用冰间湖，且个体平均会将62%的时间花费于此区域；(ii) 海豹在冰间湖内时会表现出更强的区域限制搜索行为（area-restricted search behaviour）；(iii) 海豹在冰间湖内时可获得更多能量，该能量提升以脂肪储备增加带来的浮力（buoyancy）作为指示指标。即便研究区域内无海冰覆盖，这种高质量觅食行为依然存在，这表明冰间湖是全年兼具重要性与可预测性的觅食场所。尽管利用冰间湖能带来上述能量优势，但并非所有海豹都会频繁使用此类区域。除食物供给外，其他因素或许会影响个体对觅食区域的选择，例如被捕食风险，或是能否顺利返回偏远的亚南极（sub-Antarctic）繁殖地的概率。