Hematological Parameters of Black Scorpionfish <i>Scorpaena porcus</i> Linnaeus, 1758 under Experimental Hypothermia <i>in vivo</i>

Abstract

The linear dimensions of erythrocytes, their nuclei, the number of cells and hemoglobin in the blood of the black scorpionfish Scorpaena porcus Linnaeus, 1758 were studied in the autumn-winter period, at water temperatures of 17, 13, 8 and 4˚С. The results showed high and relatively equal hemoglobin content and the number of erythrocytes in the blood of black scorpionfish at 17 and 13˚C. However, the studied parameters values at a water temperature of 13˚С were taken as the physiological norm since this temperature more corresponded with the autumn temperatures of the Karadag coast. Lowering the water temperature in the aquarium to 8˚C reduced the hemoglobin level by 25% and the number of erythrocytes by 26% in the blood of S. porcus. The linear dimensions of erythrocytes did not change when the temperature dropped to 8˚C. At a temperature of 4˚C the number of erythrocytes and hemoglobin in the blood of S. porcus rapidly decreased by 57% and by 31% respectively, and swelling of erythrocytes was observed. The large diameter of red blood cells increased by 11%, and the small diameter by 25%. The linear dimensions of the nuclei of erythrocytes increased by 12% along the major and minor axes already at a temperature of 8˚С. At 4˚C, the nuclei of erythrocytes decreased in size, along the major axis by 7%, along the minor axis by 9%, indicating a disruption of the chromatin structure in the nuclear apparatus of the cell. The results obtained made it possible to carry out a clear gradation of the temperature resistance of S. porcus. At water temperatures below 8˚С, destructive processes occurred in the blood, indicating the exhaustion of protective reserves in this species of fish. The data obtained can be used in fish mariculture as indicators of resistance to temperature factors.