In September 2016, a marine ecosystem survey covered all trophic levels from phytoplankton to seals in the Arctic Ocean to the west and north of Svalbard. At the ice edge, 26 harp seals were sampled to assess whether recent environmental changes had affected their diets and body condition by comparing our current results with previous investigations conducted 2–3 decades ago in the northern Barents Sea, when the ice edge was located much further south. Our results suggest that the body condition was slightly but significantly lower for one year and older seals in 2016 compared with seals sampled in the early 1990s. Furthermore, we confirmed previous findings that polar cod (Boreogadus saida) and the pelagic hyperiid amphipod Themisto libellula still dominate the seal diet. One consequence of current ice edge localisation north of Svalbard is that the water depth underneath is now 500 m and deeper, which probably explains the absence of bottom associated species, and the presence of species such as Atlantic cod (Gadus morhua) and blue whiting (Micromesistius poutassou) as alternative species in addition to polar cod and T. libellula in the seal diets. Stable isotope data also suggest possible long-term importance in the seal diet of T. libellula and of low trophic level benthopelagic prey such as the squid Gonatus fabricii over mid-trophic level pelagic fishes, but with a strong component of small, benthopelagic fish such as blue whiting. The long-term importance of pelagic crustaceans was also suggested from the fatty acid analyses. Assessment of the abundance of prey showed that T. libellula was by far the most abundant prey species in the upper water layers, followed by krill (mainly Thysanoessa inermis), Atlantic cod and polar cod. Prey-preference analyses indicated that polar cod was the most preferred prey species for the seals.

2016年9月，一项海洋生态系统调查涵盖了从浮游植物到斯瓦尔巴特群岛以西和北部北冰洋海豹的所有营养级别。在冰缘，取样了26枚竖琴海豹，通过将我们目前的结果与2-3年前在巴伦支海北部冰缘位于很远的地方进行的调查相比较，来评估最近的环境变化是否影响了他们的饮食和身体状况更南。我们的结果表明，与1990年代初采样的海豹相比，2016年的身体状况略微但显着降低，2016年的海豹年龄更大。此外，我们证实了先前的发现，即鳕鱼（极地鳕）和上层双节肢动物两栖纲Themisto libellula仍然主宰海豹的饮食。当前斯瓦尔巴德群岛北部冰缘定位的一个结果是，其下方的水深现在为500 m或更深，这可能解释了没有底部伴生物种以及大西洋鳕（Gadus morhua）和蓝鱼等物种的存在（在海豹的日粮中，除了极地鳕鱼和T. libellula外，还可以选择Micromesistius poutassou）。稳定同位素数据也表明在密封的饮食可能长期重要性T. libellula的，如鱿鱼和低营养水平底中水层的猎物Gonatus fabricii在中营养水平的中上层鱼类中，但具有小型底栖上层鱼类的强烈成分，例如蓝鳕鱼。脂肪酸分析还表明了浮游甲壳类动物的长期重要性。在丰富的猎物的评估表明，T. libellula的是由上层水层迄今为止最丰富的猎物，其次是磷虾（主要是Thysanoessa麦），大西洋鳕鱼和鳕鱼极性。猎物偏好分析表明，极性鳕鱼是海豹最喜欢的猎物。