半滑舌鳎工厂化人工育苗工艺技术研究

Technique and technology of productive scale seedling rearing of Cynoglossus semilaevis Günther

对半滑舌鳎（Cynoglossus semtilaevis）采取控温控光和营养强化培育等措施，使67尾经过驯养的野生亲鱼性腺全部发育，并自然产卵和受精，其中，32尾雌鱼产卵14350mL，包括浮卵4635mL，浮卵率32．5％。在水温（23±1）℃，盐度30±2，pH8.0～8．2的孵化条件下，32～36h孵化出仔鱼，初孵仔鱼约350万尾，总孵化率82．6％。90尾2＋龄人工亲鱼中，部分亲鱼性腺发育成熟，其中，雌鱼占13．2％，雄鱼占30％，但均未产卵或排精。12个鱼苗培育池先后放人人工初孵仔鱼199万尾，在（23±2）℃水温条件下，经过70d的培育，共培育出全长30～50mm的商品苗种61．5万尾，成活率30.9％，平均出苗量2050／m^3，实现了半滑舌鳎的工厂化人工苗种繁育。

The experiment was conducted from 2003 to December 2004 in a seedling farm in Qingdao. The parternal Cynoglossus semilaevis Günther were got from the Yellow Sea population near Qingdao at the age of 2 - 5 years and cultured to adult. The average body weight of the parternal fish was 2 315 g and average body length was 320 into. Water salinity was controlled at 28 -32, pH 7.6- 8.2,DO≥6 mg/L, water depth 800 mm and light intensity 100 - 500 lx. The ratio of female to male was 1 ： 1.1 and the density was 2 - 3 ind/m^2. The food for the parents fish was clamworm, small fish, shrimp, clam and oyster, but the clamworm was the most suitable food. Their gonad mature degree was determined according to the rate of gonad length to body length. Sixty-seven wildly-captured parent fish were all sexually maturated, spawned and fertilized at ease, and totally 14 350 mL of eggs were got, among which floating eggs were 4 635 mL, floating egg rate 32.5 %. Totally 3 500 000 larvae were obtained under the hatching conditions of water temperature（23 ± 1） ℃,salinity （30±2） and pH 8.0 - 8.2. Hatching time was 32 - 36 h. Among the 90 artificially-caltured parent fish at 2 ＋ years old, only part of them matured in sexual gland, but neither spawning nor sperming. Totally 1 990 000 larvae were cultured in the 12 culture ponds at water temperature （23 ± 2） ℃ ,and 615 000 of post larvae （total length 30 - 50 into） were obtained after 70 d and the survival rate was 30.9 %, averaging 2 050 ind/m^3.