Abstract:

An artificially bred protocol, developed for wild Gnathanodon speciosus, also named as golden trevally, was presented in this study. The embryonic development and growth process of the fish was also introduced. The wild fish were domesticated from 2017 to 2023. The fertilized eggs laid by naturally matured fish were transparent and buoyant. Single oil globule ((0.23 ± 0.02) mm in diameter) was observed in the yolk sac of eggs ((0.85 ± 0.04) mm in diameter). The number of eggs per gram was (3197 ± 210). The embryonic development went through six stages: cleavage, blastocyst, gastrulation, neuroblast, organogenesis and hatching. The hatching of fertilized eggs took 17 h 17 min and the hatching rate was 94.95% in sea water (salinity 30‰, pH 8.0 ~ 8.2, DO 6.05 ~ 7.13 mg∙L^-1) at (18 ± 0.5) ℃. The ecological accumulated temperature was 483.84 ℃·h. The body length of newly hatched larvae were (2.01 ± 0.14) mm. The nurture of fish fingerlings went through four stages: early larval, late larval, juvenile and fingerling, and took 45 dph with a 32.62% survival rate in sea water (salinity 26‰~32‰, pH 7.8~9.0, DO 4.90~7.50 mg∙L^-1) at (29.5 ± 2.0)℃. The transformation from juvenile to fingerling fish was completed at 26 dph. At 45 dph of growth, the fingerling fish ((51.05 ± 4.81) mm in body length) were similar to adult fish in body shape and color. This study indicated that the golden trevally grew and spawned naturally in artificial bred condition and could be artificially reproduced.

Key words: Gnathanodon speciosus, domestication, artificial propagation, seedling production