Mercury Concentrations and Se:Hg Molar Ratios in Flyingfish (Exocoetus volitans) and Squid (Uroteuthis chinensis)

We measured total mercury (Hg) and selenium (Se) concentrations as well as stable nitrogen (N) isotopic composition in flyingfish and squid muscle tissues from the eastern Indian Ocean and western South China Sea. The results showed that the mean Hg concentration in squid muscle from the western South China Sea was lower than that in the eastern Indian Ocean. The Hg concentrations in flyingfish and squid muscle samples were positively correlated with organism size (length and weight) and delta N-15 in all the study areas. Furthermore, we found a negative correlation between Se and Hg in molar content of flyingfish and squid muscle from the western South China Sea. The Se:Hg molar ratio was significantly negative correlated with fish weight and delta N-15, suggesting that the Se:Hg molar ratio decreases with the increase of fish size and trophic level in the food web.