Relationship of Size and Mass Characteristics, Indicators of Metabolism, and Mercury Concentration in the Muscle Tissue of Freshwater Fish from Tropical Vietnam

Abstract

The main chemical composition and content of mercury in the muscles of freshwater fish species Xenentodon cancila, Notopterus notopterus, Anabas testudineus, Channa striata, Ch. gachua, and Clarias batrachus from the Cái River in Southern Vietnam, as well as their body sizes, have been studied. The trend of the more intensive accumulation of mercury, protein, and lipids in the muscle tissue of females when compared with males was revealed. A significant relationship between the content of mercury and body size, as well as the content of mercury and the proportion of protein in the muscles, has not been established in most of the studied individuals. Trophic patterns of mercury accumulation in fish muscles has been confirmed: its content increases from euryphages to zoophages (facultative predators). An exception is the euryphage Clarias batrachus, which surpasses many facultative predators in mercury content. It is shown that individuals of the same species living in the biotopes of the Cái River with different hydrodynamic and hydrochemical conditions differ in weight, length, content of protein, lipids, and mercury in muscle tissue.