Study on artificial propagation and early development of Acrossocheilus longipinnis

Acrossocheilus longipinnis is a rare fish and an economically important species in the Hongshui River. To achieve large-scale production of A. longipinis fry and provide technical guidance for its proliferation and release, artificially domesticated A. longipinnis were intensively cultivated and induced to produce fertilized eggs by dry fertilization. The embryonic and larval development was observed. Four times of artificial inductions were performed. The oxytocin rate was (68.95±13.26)%, the fertilization rate was (68.50±19.82)%, and the hatching rate was (80.00±10.23)%. The fertilized eggs of the A. longipinnis were sedimentary, weakly viscous and golden in color. The egg diameter of the yolk was (2.42±0.06) mm, and the expansion of water absorption was (3.03±0.08) mm. The embryonic development process went through a total of 7 stages and 28 periods including blastogenesis stage, cleavage stage, blastocyst stage, gastrum stage, neuroembryo stage, organogenesis stage and hatching stage. The membrane was hatched after 66−74 h at the water temperature of 22−24 ℃, with an accumulated temperature of 1 501.13 ℃·h. The total length of the newly hatched larvae was (8.33±0.23) mm, with 34 pairs of sarcotomes. At 4 days after hatching, the larvae formed 5 transversely spotted embryonic prototypes. The yolk sac stage lasted for 8 d, with a total length special growth rate of 4.13%·d⁻¹. The larvae stage lasted for 21 d, with a special growth rate of total length of 2.70%·d⁻¹. The results are important for protecting A. longipinnis resources and diversity of the Hongshui River.