The content of trace elements in mullet muscle tissue (Liza aurata, Risso, 1810) of the Caspian Sea

The species diversity of the organisms of the Caspian Sea is characterized by the presence of not only endemic species, but also introduced species. Special attention should be paid to the singyle mullet (Liza aurata, Risso, 1810), which was introduced from the Black Sea in the 1930s. Based on ichthyological materials collected in 2020-2023 in the middle part of the Caspian Sea, a biological analysis and analysis of chemical elements (zinc, cadmium, nickel, manganese, iron, copper, chromium, cobalt, lead) in the muscle tissue of the Caspian crocodile was carried out. 178 specimens (75% females and 25% males) were subjected to biological analysis. Most of the copies were four- and five-year-olds. It was found that the levels of trace elements in the organisms of females and males are different. The average content of iron, zinc, and chromium in the muscle tissue of female mullets is higher than that of males, and the concentration of copper, cadmium, nickel, manganese, and lead is higher in males than in females. The cobalt content is the same for all age groups of female and male mullets. The minimal accumulation of trace elements is noted in two-year-olds, this is due to their low weight. The iron content in the muscle tissue of females is significantly higher than that of males. With age, iron and cadmium accumulate in the muscle tissue of both sexes of the male. Female and male mullets show a decrease in the concentration of lead, manganese and nickel with age, as muscle tissue is highly metabolized under conditions of increased physical activity, which increases the need for trace elements.