Mercury is a typical global pollutant.Elemental Hg,which is highly volatile,has a residence time in the atmosphere of 0.5 to 2 years,and therefore can be redistributed globally after emissions.Hg and its compounds,particularly its organic form,methylmercury(MeHg),exhibits strong biological toxicity,rapid bioaccumulation and bioamplification rates and a long biological half-life in the brain.Fish consumption has been considered to be the primary pathway of MeHg exposure for most of population because Hg mostly(70-100%)present in fish as the form of MeHg,although rice may also contribute significantly to MeHg exposure of residents living in some heavily Hg-contaminated sites of Guizhou.China is presently considered to be one of the worlds leading producers,users and emitters of mercury(Hg)due to its rapid economic development in the past 30 years.However,a national mapping of Hg concentrations in fish in China is lacking.Furthermore,the physical,chemical and biological mechanisms of Hg bioaccumulation in fish with widely geographical variation in China is largely unknown.In this review,fish Hg data of approximately 300 available literature were collected,including both English and Chinese journal articles as well as master and Ph.D.theses.The preliminary results show that the Hg concentrations in both freshwater fish and marine fish,whether for farmed fish or wild species,with a few exceptions,exhibit very low Hg concentrations well below the Chinese national standard limit of 0.5 mg/kg even in heavily contaminated Hg mining areas [the average Hg concentrations in all of 11,313 fish samples is 0.087 mg/kg(ww); only for English literature],which are totally different compared with other counties and areas,such as U.S.Canada,North Europe,Japan etc.One of motivations of this review was to provide new insights into the low accumulation in fish in China(including wild freshwater fish and wild marine fish,in addition to farmed fish),although high Hg contaminations have been commonly observed in the environmental matrix in China.According to the data we collected,the national fish product was only approximately 50 million tones in 1978,but this number has significantly and gradually increased to approximately 500 million tones in 2010; however,the corresponding amount of wild fish product has not shown the same increase since 1998,and even significantly decreased after 2006.Although there are many physical,chemical and biological factors influencing the Hg bioaccumulation in fish,our data suggest that one of the most important reasons for the generally low mercury levels in fish in aquatic environments in China is likely related to direct human activities,especially overfishing activities during the past 30 years since the reform and opening policy of China in 1978.