Some countries have established fish advisories to manage fish consumption to minimize methylmercury exposure. Our objective was to compare the fish advisories and the resultant consumer behavior in the United States of America (USA) and Japan. Both countries have national consumption guidelines, but American states enjoy greater independence in issuing guidelines for local water bodies and vary in the information that is provided for the public. The proportion of the American public that has heard of state fish advisories is thought to be close to 30%. There is a concern that this low level of awareness extends to pregnant women. In Japan, the current problem is the lack of comprehensive studies on the public awareness of fish advisories. Nonetheless, there is evidence that fish consumption has decreased in both countries. In USA, there is a possibility that the strong emphasis on mercury toxicity drives the general population towards a trend of lower fish consumption. In Japan, the fish advisory encourages seafood consumption for nutritional benefits. Consequently, the decrease may be due to the shift towards a "Western diet". Also, the Japanese fish advisory seems to be less active in advocating the issue of fish consumption and mercury exposure, which may be partly responsible for the possible lesser attention of the consumers. Cultural factors may explain for the baseline difference in consumption and account partly for the change in Japanese consumer behavior. However, the dissimilarities in fish advisories may also be responsible for the variations in consumer behavior. [ABSTRACT FROM AUTHOR]