A warming climate has driven rapid physical changes in the Arctic environment, particularly in the Bering Sea. Biological changes are also increasingly evident in the Bering Sea and adjacent waters. The ecological results have been profound and relatively well documented for fishes and lower trophic levels. Upper trophic predators such as marine mammals, however, have been underrepresented in ecosystem surveys, models, and efforts to practice ecosystem-based fisheries management. We used multiple linear regression to model body condition (mass/length) as a function of species, age class, sex and year for ribbon and spotted seals in the Bering Sea, and harbor seals in the Aleutian Islands, from 2007 to 2018, for evidence of recent trends that might reflect trophic or bottom-up changes in the ecosystem. Model-averaged coefficients (in kg cm⁻¹, relative to the overall mean) indicated that body condition was lower for subadults (−0.063; 95% CI: −0.074 – −0.051) and pups (−0.120; 95% CI: −0.129 – −0.112) than for adults (0.183, the negative sum of the subadults and pups coefficients). Body condition for males (0.010; 95% CI: 0.002–0.019) was higher than for females (−0.010). Overall, body condition declined annually (−0.014 per year; 95% CI: −0.025 – −0.004), and there was an additive annual decline in body condition of seal pups across all species and sexes (−0.020; 95% CI: −0.030 – −0.011). An additive annual increase in body condition of spotted seals across all sexes and age classes (0.013; 95% CI: 0.004–0.022) mitigated the annual declines for this species. Model-averaged fitted values therefore indicated annual declines in body condition for ribbon and harbor seals of all sex and age classes, and for spotted seal pups. We relate these declines to the trend in Bering Sea ice extent and to recent, rapid changes brought on by the significant Northeast Pacific marine heat wave of 2014–2016 and its lingering effects through 2018 and 2019. The results indicate that these typically resilient, long-lived, generalist predators can be impacted by bottom-up forcing.

气候变暖促使北极环境，特别是白令海的自然物质发生了迅速变化。在白令海和邻近海域，生物变化也越来越明显。生态结果是深刻的，对于鱼类和较低的营养水平也有相对较好的记录。但是，在生态系统调查，模型和实践基于生态系统的渔业管理的努力中，诸如海洋哺乳动物之类的高级营养掠食者的代表性不足。我们使用多元线性回归模型对白令海带状斑斑点海豹和阿留申群岛斑海豹从2007年至2018年的物种，年龄，性别和年份作为物种，年龄类别，性别和年份的函数进行建模，最近趋势的证据，可能反映了生态系统中的营养或自下而上的变化。模型平均系数（以kg cm为单位）^-1，相对于总体平均值）表明，亚成人（-0.063； 95％CI：-0.074 – -0.051）和幼崽（-0.120； 95％CI：-0.129 – -0.112）的身体状况低于成人（0.183 ，即子成人系数和幼犬系数的负和）。男性的身体状况（0.010； 95％CI：0.002-0.019）高于女性（-0.010）。总体而言，身体状况每年都在下降（每年-0.014； 95％CI：-0.025--0.004），海豹幼崽的身体状况在所有物种和性别上都有逐年下降的趋势（-0.020； 95％CI：- 0.030 – -0.011）。所有性别和年龄段的斑海豹的身体状况逐年增加（0.013； 95％CI：0.004-0.022），减轻了该物种的逐年下降。因此，模型平均拟合值表明，所有性别和年龄段的海豹和斑海豹，以及斑海豹幼崽的身体状况每年都在下降。我们将这些下降与白令海冰面积趋势以及2014-2016年东北太平洋重大海浪带来的近期快速变化及其在2018年和2019年的挥之不去的影响联系在一起。结果表明，这些趋势通常具有韧性，长期性。自下而上的强迫会影响生活中的通才捕食者。