ON THE BREEDING HABIT OF TRACHIDERMUS FASCIATUS HECKEL

Trachidermus fasciatus Heckel is a catadromous fish breeding in the coastal regionof the sea. In May and June the young fish migrates to the river where it grows for se-veral months and attains to maturity. In the later November the adult fishes begin todescend to the sea for spawning. A spawning ground is found in the south of the HuangHai, it is a small island, 5 knots away from the coast where the salinity varies from30‰ to 32‰ and the water temperatur about 4--5℃ in the breeding season. From themiddle of February to the middle of March, the male fish arrives to the spawning groundearlier than the female. Eggs are adhesive and laid in clumps attaching to oyster shellswhich form small caves in the big pile of shells on the oyster reef in the intertidal zone,the female leaves the cave as soon as the eggs being laid and the male fish remains totake care the eggs. The eggs hatch about in 26 days. The yolk sac of the fry absorbs in14 days. The young fishes begin to aggregate in the coastal region at the late April andreach to a peak in the middle of May.