We studied the effects of temperature and salinity on the egg development and hatching rate of chub mackerel
Scomber japonicus under laboratory culturing condition. The fertilized eggs were transparent, spherical, separate
in shape and turned out to be separately and floated, and they contained one oil globule. Fertilized eggs are
0.91~1.33 mm in diameter. The time of egg development was positively proportional to water temperature with
70 hrs, 48 hrs, 42 hrs, 34 hrs, after fertilization in 16℃, 20℃, 24℃, 28℃, respectively. Hatching rate was highest
with the range of 20~24℃ and 33~35 psu. The relation between the time of egg development (t: hour) and water
temperature (T:℃) was represented by the mathematical formulae. The mean biological minimum temperature was
6.9℃.