The effect of sudden changes of water temperature (WT) on the survival rate and physiological responses of the red spotted grouper (Epinephelus akaara) were examined by manipulating WT control system for 9 days. Experimental condition was divided in two different regimes at low (from 10°C to 4°C, decreased 1℃/d) and high (from 28°C to 34°C, increased 1°C/d) WT. Survival rate of experimental fishes were observed, and determined the changes of hematological characteristics by analyzing plasma levels of cortisol, glucose, total protein, and electrolytes (Na+, Cl–, K+). No mortality was observed until low WT 6°C (144 h) and high WT 32°C (96 h), and 100% mortality was observed at low WT 4°C (216 h) and high WT 35°C (171 h). Plasma levels of cortisol and glucose increased rapidly as decreasing WT, and the loss of swimming ability and respiration response was observed at low WT 7°C and high WT 34°C conditions.

INTRODUCTION
 MATERIALS AND METHODS
  1. Fish and rearing condition
  2. Experimental procedure
  3. Survival rate
  4. Physiological and biochemical analysis
  5. Statistical analysis
 RESULTS
  1. Survival rate
  2. Cortisol and glucose
  3. Plasma AST, ALT, and total protein
  4. Plasma electrolyte levels
 DISCUSSION
 REFERENCES

• Jong Youn Park(Aquaculture Research Division, Aquaculture Research Department, NIFS, Busan 46083, Korea)
• Kyeong Ho Han(Chonnam National University, Yeosu 89626, Korea)
• Jae Kwon Cho(Aquaculture Research Division, Aquaculture Research Department, NIFS, Busan 46083, Korea)
• Kyong Min Kim(South Sea Fisheries Research Institute, NIFS, Yeosu 89780, Korea)
• Maeng Hyun Son(South Sea Fisheries Research Institute, NIFS, Yeosu 89780, Korea)
• Jae Min Park(Native Fish Business Center, Gyeongsangbuk-do Fishery Resources Development Institute, Uiseong 37366, Korea)
• Hee Woong Kang(East Sea Fisheries Research Institute, NIFS, Gangneung 25435, Korea) Corresponding Author