It is valuable to study the bioavailability of trace metal in marine fish for their ecological and commercial importance. A series of experiments were conducted to investigate the trace metal (Cd, Zn, and Se) biokinetics in two marine fish Acanthopagrus schlegeli and Terapon jarbua. Waterborne and dietary metal uptake was examined under different conditions to investigate the effects of chemical and physiological factors on the bioavailability of metals to marine fish. The metal bioaccumulation in marine fish was predicted by applying the bioenergetic-based kinetic model. The different pattern of metal uptake by marine fish from freshwater fish was expressly concerned. Marine fish were found to take up waterborne metal through the gills and the gastrointestinal tracts and the latter one...[ Read more ]

It is valuable to study the bioavailability of trace metal in marine fish for their ecological and commercial importance. A series of experiments were conducted to investigate the trace metal (Cd, Zn, and Se) biokinetics in two marine fish Acanthopagrus schlegeli and Terapon jarbua. Waterborne and dietary metal uptake was examined under different conditions to investigate the effects of chemical and physiological factors on the bioavailability of metals to marine fish. The metal bioaccumulation in marine fish was predicted by applying the bioenergetic-based kinetic model. The different pattern of metal uptake by marine fish from freshwater fish was expressly concerned. Marine fish were found to take up waterborne metal through the gills and the gastrointestinal tracts and the latter one played predominant role. The uptake conformed to the first-order model over a wide range of ambient metal concentrations. The intestine had higher metal binding affinity and capacity than the gills. The surface-binding metal after short-term waterborne exposure was abundant. The waterborne uptake of trace metals in marine fish could be affected by many factors, including Cd and Zn pre-exposure, body size, water composition, and salinity. Ambient salinity influenced waterborne metal uptake, by changing both geochemical and physiological aspects, resulting in the major difference of metal uptake between marine and freshwater fish. The assimilation efficiency of dietary metals was observed to be influenced by the subcellular metal distribution in the preys and the feeding process of the fish. Body size influenced both the assimilation efficiency and ingestion rate significantly. The metal bioaccumulation was a gross result of waterborne and dietary metal uptake and metal efflux in marine fish, which was successfully predicted by the bioenergetic-based kinetic model. Dietary metal dominated the overall metal accumulation; efflux was the key process to the metal homeostasis in marine fish. Body size is also an important factor in metal bioaccumulation, and subsequently, metal trophic transfer in marine fish. The tissue specific and subcellular metal distributions revealed the strategies of marine fish handling trace metals.