The functional morphology of erythrocytes of the black scorpion fish Scorpaena porcus (Linnaeus, 1758) (scorpaeniformes: scorpaenidae) during hypoxia

The influence of hypoxia on the morphological characteristics of circulating erythrocytes of the scorpion fish Scorpaena porcus (Linnaeus, 1758) has been investigated in an in vivo experiment. Under a 4-h adaptation of the fish to the conditions of ranked hypoxia their erythrocytes demonstrated a number of consecutive reactions. The volume and the surface area of the red blood cells was reduced by 4–5% (p < 0.001) at an oxygen concentration of 2.6 mg/L (30% saturation of water with oxygen) and increased by 4% (p < 0.001) at a concentration of 1.3 mg/L (15% saturation), relative to the control values (normoxia: 7–8 mg/L). The observed reaction of erythrocytes coincided quantitatively and qualitatively (the order of events) with the results of the experiments we performed previously in vitro. Our study has shown that the physiology of the black scorpion fish is tolerant to hypoxia and allows autonomous functioning of red blood cells under conditions of oxygen deficit.