Rapid climate warming is decreasing sea ice thickness, extent, and duration. Marine mammals such as bearded (Erignathus barbatus) and ringed (Pusa hispida) seals may be negatively affected because they use sea ice for pupping, molting and resting. Claws from bearded and ringed seals store up to 14 and 12 years of sequential analyte data, respectively. In this study, we compare progesterone, cortisol, and carbon and nitrogen stable isotopes in female bearded and ringed seals during 1954-1968 (pre-1968, a period prior to sea ice decline) to 1998-2014 (post-1998, a period during sea ice decline). When comparing these periods, bearded seals had statistically higher cortisol concentrations post-1998, and for both species δ13C was more negative post-1998. There was a positive relationship between progesterone and cortisol Z-scores for both species, except for ringed seals post-1998. A negative relationship between cortisol and δ13C in bearded seals suggests a shift to higher prey diversity, possibly due to changes in sea ice in the Pacific Arctic evident post-1998. Progesterone Z-scores corresponded to expected differences among non-pregnant, unimplanted, implanted, and post-partum individuals. Using these data, pregnancy history was determined for reproductive years for each individual female sampled which could allow for yearly pregnancy rates to be calculated given a large enough representative sample of the population. These results combine decades of observational studies with chemical analytes to infer changes and connections in reproduction, stress, and diet.