Effect of Hypoxia on Physiological-Biochemical Blood Parameters in Some Marine Fish

Changes of hematocrit, hemoglobin, and blood plasma glucose and Na⁺ and K⁺ content in response to hypoxia were studied in three Black Sea fish species. It was shown that in response to hypoxia in low-mobile rock perch Scorpaena porcus L., hematocrit and the blood plasma glucose level increased, while the content of K⁺ in erythrocytes decreased and the content of Na⁺ increased. In moderately mobile sea carp Diplodus annularis L. autogenic hypoxia caused a rise of hematocrit and blood plasma glucose. In actively swimming jack mackerel Trachurus mediterraneus ponticus Aleev, only considerable increase of Na⁺ content was revealed in hypoxia. The obtained results indicate that fish with different mobility under hypoxic conditions use different adaptation mechanisms. The value and direction of changes of the chosen parameters can be used to determine resistance of fish to oxygen deficit.