Maternal Steller sea lion diets elevate fetal mercury concentrations in an area of population decline

• DOI: 10.1016/j.scitotenv.2013.02.095
• Publication Date: 2013-03-29T19:15:46Z
• Authors: Lorrie D. Rea; J. Margaret Caste...; Lucero Correa; Brian S. Fadely; Todd M. O'Hara
• Keywords: Mercury; MERCURY EXPOSURE; Fat accumulation; δ15N

Total mercury concentrations ([THg]) measured in western Aleutian Island Steller sea lion pup hair were the highest maximum [THg] documented in this endangered species to date. Some pups exceeded concentrations at which other fish-eating mammals can exhibit adverse neurological and reproductive effects (21% and 15% pups above 20 and 30 μg/g in hair, respectively). Of particular concern is fetal exposure to mercury during a particularly vulnerable stage of neurological development in late gestation. Hair and blood [THg] were highly correlated and 20% of pups sampled in the western Aleutian Islands of Alaska exceeded mammalian risk thresholds established for each of these tissues. Higher nitrogen isotope ratios suggested that pups accumulated the highest [THg] when their dams fed on higher trophic level prey during late gestation.