Specimens of chub mackerel and round scad were killed by three different procedures, i.e. stabbing in the spinal bulb (instant killing), dipping in cold sea water (temperature shock), and leaving to die in the air (struggled killing). After death, the fishes were stored at 0°C. In chub mackerel, the rate of progress of rigor-mortis, and the rates of change of concentrations of ATP, IMP, creatine phosphate, and breaking strength of the dorsal muscle in the instant killing group were the slowest. The rates of change in the temperature shock group were almost similar to those in the struggled killing group. The K-value in the instant killing group was also lower than in the other two groups. In round scad, these was a clear difference in the post-mortem changes between the three groups.
