[Inner- and inter-species differences of mercury concentration in common fishes from the Yellow Sea]

Mercury concentration in marine fishes and its influencing factors are the key problems in the study of mercury biomagnification in marine ecosystems. In order to understand the inner- and inter-species differences of mercury concentration in fishes from the Yellow Sea, a total of 164 marine wild fishes covering nine different species were collected from the area from August to October, 2012. Mercury (total mercury) concentration in fish muscle tissue was measured by a direct mercury analyzer. Body length and wet weight of each sample were also determined. Moreover, feeding habit and trophic level of different species were examined. Hg concentrations (dry weight) in the muscle tissues of the 164 individuals ranged from 0.025 micro x g(-1) to 0.526 microg x g(-1), with an average of (0.124 +/- 0.096) microg x g(-1). By an inner-species analysis, log10 Hg concentration was significantly correlated to their body length and wet weight. Predator fishes with trophic level > 2.8 were more readily to be contaminated by Hg than the filter feeder with trophic level < 2.8. Furthermore, species with higher increasing rate of weight had lower Hg concentration in the muscle due to growth dilution. The results suggest that length and weight are the main factors affecting the inner- species difference of mercury concentration in common fishes from the Yellow Sea, while dietary preference, trophic level and increasing rate of weight are the main factors affecting the inter-species difference from the Yellow Sea.