The present study provides the complete report on the embryonic and larval development of pink ear emperor, Lethrinus lentjan (Lacepede, 1802). Eggs were obtained from captive-reared broodstock of pink ear emperors from 1-year of age maintained in a 10-tonne recirculating aquaculture system (RAS). The brood fishes spawned throughout the year without hormonal induction. Fertilized eggs (692.65 ± 6.67 µm) were pelagic, transparent, non-adhesive and with a single oil globule measuring 146.63 ± 3.51 μm. Description of the different phases of embryogenesis, namely the zygote, cleavage, blastula, gastrula, segmentation of the fish is provided. Additionally, the developments during larval development period after hatching, which extends till the completion of yolk-sac absorption (pre-larvae) and the end of metamorphosis (post-larval) are also included in the present study. The embryonic development was completed within 14 h 40 min after fertilization. The newly hatched larvae had an average body length of 1.39 ± 0.08 mm, with a yolk sac measuring 787.67 ± 42.65 µm. The mouth opening was observed at 2 days post-hatch (dph). The yolk sac was completely absorbed by 2 dph, and the preflexion stage began, and it continued till 14 dph. Notochord flexion began by 15 dph and extended to 20 dph. The appearance of the typical adult colouration and scale formation started by 22 dph and by 35 dph the larvae reached the juvenile stage. The data on the embryonic and larval development will help to standardize the larval rearing techniques for the species.

中文翻译：

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圈养条件下红耳帝王 Letthrinus lentjan (Lacepede, 1802) 的胚胎和幼虫发育

本研究提供了关于粉耳帝王Letthrinus lentjan胚胎和幼虫发育的完整报告（Lacepede，1802 年）。卵是从饲养在 10 吨循环水产养殖系统 (RAS) 中的 1 岁龄粉红耳帝王的人工养殖亲鱼中获得的。亲鱼在没有激素诱导的情况下全年产卵。受精卵 (692.65 ± 6.67 µm) 是浮游的、透明的、无粘性的，并且有一个大小为 146.63 ± 3.51 µm 的油球。描述了胚胎发生的不同阶段，即受精卵、卵裂、囊胚、原肠胚、鱼的分割。此外，本研究还包括孵化后幼虫发育期，直至卵黄囊吸收完成（前幼虫）和变态结束（后幼虫）的发展。受精后14小时40分钟内完成胚胎发育。新孵化的幼虫平均体长为 1.39 ± 0.08 毫米，卵黄囊为 787.67 ± 42.65 µm。在孵化后 2 天 (dph) 观察张口。卵黄囊在2 dph时被完全吸收，开始前屈阶段，一直持续到14 dph。脊索弯曲从 15 dph 开始并扩展到 20 dph。22 dph 开始出现典型的成虫着色和鳞片形成，35 dph 时幼虫进入幼虫阶段。有关胚胎和幼虫发育的数据将有助于规范该物种的幼虫饲养技术。脊索弯曲从 15 dph 开始并扩展到 20 dph。22 dph 开始出现典型的成虫着色和鳞片形成，35 dph 时幼虫进入幼虫阶段。有关胚胎和幼虫发育的数据将有助于规范该物种的幼虫饲养技术。脊索弯曲从 15 dph 开始并扩展到 20 dph。22 dph 开始出现典型的成虫着色和鳞片形成，35 dph 时幼虫进入幼虫阶段。有关胚胎和幼虫发育的数据将有助于规范该物种的幼虫饲养技术。