The oceans provide great health benefits to humans, ranging from food and nutritional resources to recreational opportunities and new cures for human disease. At the same time, increasingly, food from the oceans is contaminated with man-made pollutants. Globally, over one billion people rely on fish and other seafood as their main source of animal proteins (Figure 1). Dependence on a seafood diet is usually higher in coastal than in inland areas, and many small island states depend on fish exclusively, particularly native peoples. Therefore, the choice for those people who regularly consume seafood is increasingly a balance between the nutritional vs. the detrimental aspects of seafood (see case study by Dewailly, this issue).