CHARACTERIZATION OF THE FUNCTIONAL STATE OF SO-IUY MULLET PLANILIZA HAEMATOCHEILA (TEMMINCK & SCHLEGEL, 1845) IN THE AZOV SEA AT THE END OF THE WINTERING PERIOD

Abstract

. The physiological state of a sample of so-iuy mullet Planiliza haematocheila (Temminck & Schlegel, 1845) from the Azov Sea at the end of its wintering period is analyzed. The state of females and males was assessed by the content of total protein, moisture and lipids in the muscles, liver and gonads, by protein content, including albumin and globulins, cholesterol, triglycerides in the blood serum, and by the characteristics of the variation series of oocyte diameters in females. The reduced content of protein and fat in the muscles and liver, fat in the gonads of females, and carotenoids in the liver and gonads is noted in comparison with the long-term data characteristic for the early spring period. The content of protein, cholesterol and triglycerides in blood serum was also reduced. Values of protein coefficient (albumin-to-globulin ratio) did not exceed 0.73, which is not typical for this blood serum parameter (normally above 1.0). The dynamics of the investigated biochemical parameters of blood indicated an insufficiently active transport of nutrients, in particular albumin and triglycerides, to the organs and tissues. The females had gonads of the 3 rd maturity stage; diameter of the oocytes reached 0.25– 0.35 mm, and larger oocytes have not been recorded in the majority of the investigated fish individuals, which suggests a lower degree of gonadal maturity during this period. Satisfactory physiological state of the so-iuy mullet at the end of its wintering is associated with a significant decrease in temperature in early November 2018, which led to a decrease in the duration of autumn feeding and to an earlier onset of the wintering period.