Global mercury and selenium concentrations in skin from free-ranging sperm whales (Physeter macrocephalus)

► Mercury (Hg) is a priority pollutant for the oceans. ► Hg concentrations worldwide were surveyed in the skin of free-ranging sperm whales ► Global mean mercury concentrations in sperm whale skin were 2.5 μg g− 1 ww. ► Mediterranean Sea had the highest mean mercury concentration of 6.1 μg g− 1 ww ► Selenium concentrations suggest a protective effect against mercury toxicity.