Predicting how climate change threatens the prey base of Arctic marine predators

<b>Abstract</b><br/><p>Arctic sea ice loss has direct consequences for predators. Climate-driven distribution shifts of native and invasive prey species may exacerbate these consequences. We assessed potential changes by modelling the prey base of a widely distributed Arctic predator (ringed seal; Pusa hispida) in a sentinel area for change (Hudson Bay) under high- and low-greenhouse gas emissions scenarios from 1950 to 2100. All changes were relatively negligible under the low-emission scenario, but under the high-emission scenario, we projected a 50% decline in the abundance of the well-distributed, ice-adapted, and energy-rich Arctic cod (Boreogadus saida) and an increase in the abundance of smaller temperate-associated fish in southern and coastal areas. Further, our model predicted that all fish species declined in mean body size, but a 29% increase in total prey biomass. Declines in energy-rich prey and restrictions in their spatial range are likely to have cascading effects on Arctic predators.</p>

<b>摘要</b><br/><p>北极海冰消退对北极捕食者具有直接影响。气候驱动下本土与入侵猎物物种的分布迁移，可能会进一步加剧这些影响。本研究以监测气候变化的哨兵区域哈德逊湾为研究区，针对广泛分布的北极捕食者——环斑海豹（ringed seal, *Pusa hispida*）的猎物群落，在1950年至2100年的高、低两种温室气体排放情景下开展建模，评估其潜在变化。在低排放情景下，所有变化均相对可忽略；但在高排放情景下，研究预测分布广泛、适应海冰且富含能量的北极鳕（Arctic cod, *Boreogadus saida*）的丰度将下降50%，而南部及沿岸区域与温带相关的小型鱼类丰度则会上升。此外，模型预测所有鱼类的平均体型均出现下降，但总猎物生物量将增加29%。富含能量的猎物资源减少及其空间分布范围受限，很可能会对北极捕食者产生级联效应。</p>