To reduce mass mortality of Pacific saury caused by collision with the tank wall, we examined rearing of saury in a tank with a vinyl sheet attached to the tank wall, and no vinyl sheet tank. We compared survival rate and ratio of the lower jaw length to the knob length of those fish. Survival rate of the former was higher than the latter. No significant difference was recognized for the ratio. These results suggest that the vinyl sheet could not reduce the damage to the lower jaw, but it could reduce the mortality caused by collision
