Embryonic and Morphological Development in the Larva, Juvenile, and Young Stages of Epinephelus fuscoguttatus (♀) × E. lanceolatus(♂)

Abstract:

The current study investigated the Epinephelus fuscoguttatus(♀) × E. lanceolatus(♂) hybrid embryo and larvae in the terms of the morphological characteristics to provide a basis for the future breeding. The results show that embryonic development required 25 h 25 min at 27−28℃. The embryonic developmental process included five stages: cleavage stage, blastula stage, gastrula stage, nerve stage, and organogenesis stage. The post-embryonic development included larval, juvenile, and young fish stages at (27±0.5)℃, salinity 30, and pH 8 based on the features of the yolk sac, second dorsal fin spine, pelvic fin spine, scales, and body color. Larval was further divided into early and late larval larvae according to the presence or absence of yolk sac. Newly-hatched to 4-day was the early larvae, and larvae hatching yolk sac completely disappeared at 5 d. Fifty percent of larvae entered larval period at 32 d. Fifty percent larval completed the metamorphosis that developed into juvenile fish. The average total length of newly-hatched larvae was (1.65±0.11) mm, reaching (75.47±0.19) mm at 70 d. These results indicated that the hybrid offspring from conception to the later stages are healthy and normally-grown and developed; the disease-resistant heterosis had the appearance of “Epinephelus fuscoguttatus head and E. lanceolatus tail”.