Krill Fatty Acid Data

The fatty acid content and composition of the Antarctic krill Euphausia superba Dana, 1850 were investigated using samples collected by a commercial fishing vessel. This dataset allowed comparison between seasons, years (2013–2016), and different fishing locations. Quantities of omega 3 fatty acids 20:5n-3 and 22:6n-3 (mg/g dry mass; DM) were highest in autumn and decreased through winter to reach a spring low. Quantities of the flagellate marker 18:4n-3 and diatom marker 16:1n-7c were variable and did not display the same seasonal fluctuations. In summer, krill had high percentages (% total fatty acids) of 20:5n-3 and 22:6n-3, total PUFA, and low 18:1n-9c/18:1n-7c ratios, indicating a more herbivorous diet. Krill became more omnivorous from autumn to spring, indicated by increasing ratios of 18:1n-9c/18:1n-7c and percentages of Σ 20:1 + 22:1 isomers. Bacterial fatty acids (Σ C15 + C17 + C19 isomers) were minor components year-round (0.9–1.8 %). Seasonal levels of herbivory and omnivory differed between years, and levels of specific fatty acid ratios differed between fishing locations. The fatty acid 18:4n-3 was a major driver of variability in krill fatty acid composition, with no obvious seasonal driver. This is the first study to report krill fatty acid data during all four seasons over consecutive years. This large-scale study highlights the value of using fisheries samples to examine seasonal and annual fluctuations in krill diet and condition.

本研究借助商业捕捞船采集的样本，对南极磷虾（Antarctic krill, *Euphausia superba* Dana, 1850）的脂肪酸含量与组成展开系统探究。本数据集支持开展季节、年度（2013–2016年）以及不同捕捞海域间的对比分析。ω-3脂肪酸（omega 3 fatty acids）中的二十碳五烯酸（20:5n-3）与二十二碳六烯酸（22:6n-3）的含量（单位：mg/g干重，DM）在秋季达到峰值，随后随冬季推进逐渐降低，至春季降至最低水平。鞭毛藻标志物18:4n-3与硅藻标志物16:1n-7c的含量波动显著，并未呈现出与上述两种脂肪酸一致的季节变化趋势。夏季磷虾的二十碳五烯酸（20:5n-3）、二十二碳六烯酸（22:6n-3）以及总多不饱和脂肪酸（PUFA）占总脂肪酸的比例较高，同时其18:1n-9c/18:1n-7c比值较低，表明此时磷虾的食性更偏向植食性。从秋季至春季，磷虾的食性逐渐向杂食性转变，这一趋势可通过18:1n-9c/18:1n-7c比值以及Σ20:1+22:1异构物占比的升高得到印证。细菌源性脂肪酸（ΣC15+C17+C19异构物）全年仅为微量组分，占比仅为0.9%–1.8%。不同年度间，磷虾植食性与杂食性的季节水平存在差异，且特定脂肪酸比值的水平也因捕捞海域的不同而有所区别。脂肪酸18:4n-3是导致磷虾脂肪酸组成产生变异的主要因素，但其自身的变化并无明显的季节驱动因子。本研究首次报道了连续四年间全季节的磷虾脂肪酸数据。这项大规模研究凸显了利用渔业捕捞样本探究磷虾食性与健康状况的季节及年度波动的重要价值。