Hematological indicators of fish of small rivers of the State Nature Reserve «Yaroslavsky»

Data on blood and blood-forming organs of species of the cyprinidae and perch family species living in the rivers of the Yaroslavsky State Nature Reserve were obtained. It was revealed that the hematocrit level in the studied species varied in the range of 23–42 %, the total number of erythrocytes was 1.29–2.20 m/μkl, and the number of leukocytes was 65.9–141.2 thousand/ μkl. The relative number of peripheral blood leukocytes varied in the range: lymphocytes 87–90 %, segmented neutrophils — 3–7.5 %, stab neutrophils — 1–4 %, monocytes and eosinophils — 1–3 %. The relative number of lymphocytes in the organs increased in the series mesonephros, spleen, and liver. The number of hemocytoblasts, on the contrary, decreased. The relative number of myelocytes and metamyelocytes in mesonephros and spleen varied from 1 to 3 %, promyelocytes — from 2 to 4.5 %. Of all the species studied in the liver, myelocytes were found only in the bersh; no hemocytoblasts and promyelocytes were found. Regardless of the organ, the relative number of macrophages, plasmocytes and eosinophils varied from 0 to 3 %, stab neutrophils from 3 to 8.5 %. The number of segmented neutrophils in the mesonephros and spleen varied from 3 to 11 %, in the liver this indicator was 1–3 %. The range of obtained values for the studied indicators was comparable with the previously obtained data for the considered fish species living in relatively clean sections of the Rybinsk Reservoir and its tributaries. It was established that the trophic status of the species exerts the greatest influence on the hematocrit level, the total number of peripheral blood leukocytes, and the relative number of leukocytes in peripheral blood and mesonephros