Abstract:
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 75.0×10
6 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 25
th day after hatching, and then powdery compound feed and granule feed had been fed since 30
th day after hatching. About 15.0×10
6 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.