Use of Caviar and Fillet Biomarker Fatty Acids to Determine the Origin of Sterlet Acipenser ruthenus (Linnaeus, 1758).

Significant differences in the fatty acid (FA) composition of caviar and muscle tissue (fillet) were found in the sterlet Acipenser ruthenus (Linnaeus, 1758) between fish from the Yenisei River and aquaculture farms and were associated with different food sources. Caviar and muscle tissue of sterlet from the natural habitat showed significantly higher levels of the FAs that provide biomarkers of diatoms and bacterial matter. Oleic and linoleic acids, which are characteristic of higher plant oils, and long-chain monounsaturated fatty acids, which are biomarkers of marine copepods, displayed significantly higher contents in sterlet grown in aquaculture, apparently originating from artificial foods. A ratio of several biomarker FAs was for the first time proposed to assay, and its threshold value was established to determine whether sturgeon caviar and fillet originate from fish from natural habitats or aquaculture.

Content of metals in compartments of ecosystem of a siberian pond.

During three field seasons (June--September) of 1997--99 contents of Na, K, Ca, Mg, Fe, Mn, Zn, Cu, Al, Cr, Ni, Cd, and Pb were determined in compartments of ecosystem (surrounding soils, bottom sediments, water, zoobenthos, macrophytes, and fish) of a fish and recreation pond situated at the edge of Krasnoyarsk City (Siberia, Russia). Contents of most parts of metals in soils, water, and macrophytes significantly correlated with each other. As concluded, their contents were determined by natural, general, geochemical peculiarities of the region. Heavy metals, contents of which were higher than federal upper limits of concentration, were revealed. In muscles of fish with different feeding spectra--crucian and perch--concentrations of some metals differed significantly; correlation graphs for metals also had different structures. Comparison of our data with those on diverse aquatic ecosystems of Siberia, Europe, North America, and China published in the last decade was carried out. It was concluded that a distribution of heavy metals in the compartments of an aquatic ecosystem presently have to be determined for each particular water body until general regularities are discovered.