Abstract:  Embryonic development of turbot (Scophthalmus maximus) was studied， and the growth characteristics as well as the changes of nucleic acids and proteins were analyzed to establish the relationship between growth traits and biochemical indexes. The major results were as follows: （1） Embryonic length changed according to the tendency of “decreaseenlargementdecreaseenlargement” at different stages， and reached the minimal value of 0998 mm at 5 h 40 min after fertilization and the maximal value of 1.089 mm at hatching. （2） Diameter of oil globule increased till cleavage stage and decreased thereafter with the appearance of the highest value of 0.192 mm at 9 h 40 min and the lowest value of 0.176 mm at 65 h. （3） Embryonic body mass increased before gastrula stage and decreased thereafter， and presented the minimal value of 0.340 mg at 7 h 30 min and the maximal value of 0.674 mg at 9 h 40 min. （4） The changes of RNA/DNA and protein/DNA ratios showed that embryonic growth was dominantly hyperplastic till blastula stage， hypertrophical till gastrula stage， hyperplastic till segmentation stage and hypertrophical till hatching， indicating that embryonic growth was periodic alternation of hyperplasia and hypertrophy. （5） The relations were binomial among morphological traits， body mass and biochemical indicators， and RNA/DNA ratio was closely correlated with growth traits.

Key words: turbot, embryonic development, nucleic acids；RNA/DNA