点篮子鱼人工繁育技术研究

2008年4~6月在海南进行了点篮子鱼的人工繁殖试验,共产卵610×104cell,孵化出仔鱼342.4×104ind,经过30 d土池生态培育,培育出体长约2.5 cm幼鱼32.5×104ind,土塘培育苗种成活率达16.1%。点篮子鱼适宜催产的环境条件为:水温25.5~27.7℃,盐度33.0~34.5,pH值7.9~8.5,DO值6.0~8.8 mg/L。A、B、C三种药品配伍进行催产效果最好,获产率、受精率、孵化率均最高,分别达到60.0%~80.0%、83.2%~90.5%和71.2%~76.8%,效应时间缩短到15~16 h。点篮子鱼受精卵为半浮性卵,孵化积温为649.25时度。当盐度低于26.5时,点篮子鱼受精卵沉于水底;盐度高于38.5时,则浮于水面。水温对胚胎发育影响较大,15℃、20℃试验组胚胎分别发育至原肠晚期、胚孔封闭期死亡,35℃条件下胚胎发育终止于胚体形成期,30℃试验组初孵仔鱼的活力差,畸形率高。点篮子鱼胚胎发育的适温为25℃左右。盐度对点篮子鱼的胚胎发育的影响较大。在盐度34.4~45.7范围内,随着盐度的增加,孵化率降低,畸形率升高。在盐度30.2~34.4范围内,孵化率在60%以上,畸形率在10%以下,最适盐度范围30.2~34.4。初孵仔鱼全长为1.00~1.20 mm,油球一个,出膜3~4 d开始摄食小型轮虫和藻类。点篮子鱼苗15日龄前生长缓慢,之后生长迅速,平均全长与日龄回归方程式为:y=1.120 7e0.109 4x,R2=0.979 5。

Study on artificial propagation of Siganus guttatus

The artificial propagation technology of Siganus guttatus has been conducted in Hainan Province during April to June of 2008.The total spawn was 6100 thousand cells and hatched larva-fish were 3424 thousand individuals.About 325 thousand juvenile fish with the total length 2.5 cm were cultivated in outdoor ponds after 30 days.The survival rate of juvenile fish was 16.1%.The optimal environmental factors for Siganus guttatus were as follows: the range of water temperature was 23-25 ℃,salinity 33.0-34.5,pH 7.9-8.5 and DO 6.0-8.8 mg/L.The induced spawning effect was best when three kinds of drugs A、B、C were compatibly mixed,and the rates of spawning,fertilization and hatching rate were 60.0%-80.0%,83.2%-90.5% and 71.2%-76.8%,respectively,the effective time would be shorten to 15-16 hr.Fertilized eggs of Siganus guttatus were semi-floating eggs.The accumulative temperature was 649.25 ℃·h.The temperature has great influence on fetation.Death happened when the embryo developed to late gastrula at 15 ℃ and closure of blastopore at 20 ℃,respectively.The fetation was terminated in embryogeny stage when the temperature was 35 ℃.Activity of newly hatched larvae was not good at 30 ℃ with higher deformity rate.The optimum temperature of fetation for Siganus guttatus was about 25 ℃.The effect of salinity on fetation of Siganus guttatus was great,hatching rate declined and deformity rate rose with the increasing of salinity whose range was 34.4-45.7ppt.,hatching rate was up to 60% and deformity rate was under 10% when the salinity was 30.2-34.4ppt.The total length of newly hatched larvae was 1.00-1.20 mm with an oil-globe.Newly hatched larvae could feed minitype rotifer and unicellular algae after 3 or 4 days hatching.Larvae grew slowly before 15 days and then became rapidly.The regression equations between average total body length and days after hatching was y=1.120 7e0.109 4x,R2=0.979 5.