Closer to shore, higher mercury? Interannual variation in exposure and foraging ecology in common murres.

Higher mercury levels in common murres during 2022, with concentrations reaching up to 1.12 μg/g wet weight, coincided with shifts to coastal and benthic foraging.

• Why it matters: Understanding short-term variation in mercury exposure is crucial for assessing risks to marine top predators and managing environmental health, yet these drivers are poorly understood.
• What they did: Researchers measured red blood cell mercury levels, tracked foraging behavior with GPS and TDR devices, and analyzed stable isotopes over two breeding seasons (2021-2022) in the Gulf of St. Lawrence.
• The result: Findings reveal significant interannual variability linked to ecological shifts and environmental mercury availability, emphasizing the importance of combining contaminant data with fine-scale tracking to interpret exposure patterns.