Water temperature is one of the most important factors of fish survival, affecting the habitat, migration route, development, and reproduction. This experiment studied the induction level of heat shock protein (HSP70) mRNA and protein in a walleye pollock (Gadus chalcogrammus) primary hepatocyte culture based on different temperatures. Hepatocytes were attached at 7.5 °C for 24 hours. Hsp70 induction levels were then measured for 48 hours at 5, 8, 11, 14, and 17 °C. The induction level was lowest at 5 °C and generally increased with temperature until 14 °C. The induction level was reduced at 17 °C, indicating that 14 °C is the highest tolerable temperature for hepatocytes. These data indicate that primary hepatocyte cell culture is under no stress at 5 and 8 °C. Temperatures greater than 11 °C induce stress, showing similar induction patterns in both mRNA and protein in hepatocytes. The results suggest that 14 °C is the maximum internal defense temperature of walleye pollock survival.