广东池塘培育四指马鲅亲鱼初次性成熟和苗种规模化繁育技术研究

于2015年6月~9月在广东珠海对人工孵化和培育的2龄四指马鲅(Eleutheronema tetradactylum)亲鱼的初次性成熟和产卵情况以及苗种规模化全人工繁育技术进行了系统的观察和研究。结果显示,实验期间培育亲鱼2 000余尾,成熟率93%以上。成熟亲鱼的体质量雌雄之间差异较大,雌鱼性腺指数(GSI)为1.03%~6.05%,雄鱼GSI为0.26%~1.76%。雌鱼产卵类型为一年产卵1次,分批成熟、分批产卵,初次性成熟的产卵期从2015年6月13日~9月30日。共计产卵75.0×106粒,受精率为72%~95%,胚胎发育在盐度27~28.8、温度29~31℃、p H 8.1~8.3条件下历时13 h 52 min,孵化率为58%~95%。仔鱼在室内培育,投喂小球藻和轮虫,5~7 d后转移到室外土池进行培育,7 d后投喂小球藻、轮虫、枝角类和桡足类幼体。第25天起投喂卤虫无节幼体,第30天起投喂粉状配合饲料并逐渐过渡到投喂人工颗粒饲料。从2015年7月23日开始至9月30日累计培育出子二代苗15.0×106尾,平均成活率为25.0%。综合亲鱼产卵和幼苗育成情况,认为该鱼全人工繁育的技术关键在于如何培育优质的亲鱼以及育苗过程中水质的控制和适口饵料选择及其适时更换。

First maturation and mass seedling propagation of cultured Eleutheronema tetradactylum in Guangdong Province

We studied the first maturation and spawning of 2-year-old cultured Eleutheronema tetradactylum and seedling mass production from June to September,2015.The result shows that more than 2 000 broodstocks were maintainced during the experiment with maturation rate of over 93%.There was significant difference in body weight between male and female broodstocks.The gonadosomatic index (GSI) of female was 1.03%~ 6.05%,while that of male was 0.26%~1.76%.The breeding pattern of female was batch maturating and spawning,with laying eggs once a year;and the spawning period of female with the first maturation lasted from June 13,2015 to the end of September.About 75.0×106 eggs were produced with fertility rate of 72%~95%.The embryonic development finished in 13 h 52 min at 29~31 ℃,salinity of 27~28.8 and pH of 8.1~8.3,with hatching rate of 58%~95%.Newly hatched larvals were reared in indoor tanks for 5~7 d with Chlorella sp.and rotifer as foods,and were transferred to outdoor ponds afterwards,with feeding cladocera and copepods.Nauplius of Artemia sp.was fed since 25th day after hatching,and then powdery compound feed and granule feed had been fed since 30th day after hatching.About 15.0×106 fries of second filial generation were harvested from July 23 to September 30,2015,with an average survival rate of 25%.The keys for complicated artificial propagation of this species are management of qualified broodstock,water quality control and in time feed change.