Mercury (Hg) analyses in species of fish are performed for two reasons 1) to safeguard human health, 2) to assess environmental quality, since different environmental changes may increase the Hg concentrations in fish. These analyses are important since both natural and human activities can increase these Hg concentrations, which can vary extensively, depending on the species, age and catching location. Unfortunately, humans consuming Hg contaminated fish or other marine foodstuffs cannot taste Hg contamination; this can be only detected by chemical analysis. If the aim of Hg analysis is to protect the health of marine-food consumers, researchers workers must consider the location where the fish were caught and interpret the results accordingly. Health and environmental officials must appreciate that in specific places many local people may have a daily diet almost entirely consisting of fish or other marine foods, and these individuals should not be exposed to high concentrations of Hg. Regional and national health and environmental officials should follow the guidance of international organizations when drawing their final conclusions about whether or not the products are safe to eat.