Interspecific and intraspecific variation in selenium:mercury molar ratios in saltwater fish from the Aleutians: Potential protection on mercury toxicity by selenium

► Selenium:mercury molar ratios were examined in Aleutian fish. ► Mean ratios for all fish were above 1:1. ► Some individuals of six species had ratios below 1. ► Ratios below 1 are thought not to be protective for human health.