Acute stress response (cortisol, glucose, Na+, K+, Cl-, Total protein, ALT, AST, hematocrit, red blood cell count, hemoglobin amount, MCV, MCH and MCHC) and changes in physiological conditions according to the salt and density of the breeding water (Survival rate, growth, feed efficiency and obesity, etc.) were investigated. Plasma cortisol concentration in the stress response of acute salinity change of flounder raised with low salinity was from 4.4±1.9 ng/ml at the start of the experiment to 3.7±1.9 ng/ml at 3 hours and 2.8±1.1 ng/ml at 24 hours for 35‰ fish. While there was no difference, the 0‰ sphere showed no difference at 2.0±0.1 ng/ml at 3 hours, but showed the highest value at 47.9±18.6 ng/ml at 24 hours. The Na+ concentration did not show a difference from 166.8±10.7 mEq/L at the start of the experiment to 164.5±2.5 mEq/L in the 0‰ sphere at 3 hours, but decreased significantly to 149.0±9.4 mEq/L at 24 hours. The 35‰ sphere showed no difference from the start of the experiment.
The AST value was 26.3±11.4 IU/L at 24 hours in the 0‰, which was about 2 times higher than 12.0±2.2 IU/L at the start of the experiment. In the stress response of low salinity to low water temperature and anesthesia transport, the cortisol concentration before transport increased from 2.4±0.1 ng/mL to 16.7±12.8 ng/mL in CWT+35‰, but there was no significant difference, whereas NWT+35‰. The sphere increased to 47.9±19.8 ng/ml, showing a difference. The NWT+15‰ group increased significantly to 43.5±13.9 ng/ml and the CWT+15‰ group increased to 26.1±8.3. The NWT+15‰+Anes. group increased to 61.7±3.3 ng/ml, and the CWT+15‰+Anes. group showed the highest value at 86.1±19.0 ng/ml. The K+ concentration slightly increased from 3.1±0.0 mEq/L before transport to 4.5±1.1 mEq/L in the NWT+15‰ group, showing no difference, and significantly increased in all other experimental groups.