云纹石斑鱼胚胎发育及仔、稚、幼鱼形态观察

Embryonic development and morphological characteristics of larval, juvenile and young Kelp bass, Epinephelus moara

关键词:  云纹石斑鱼  胚胎发育  仔鱼  稚鱼  幼鱼  形态特征

Key words:  Kelp bass  Embryonic development  Larvae  Juvenile  Young fish  Morphological characteristics

摘要:

对云纹石斑鱼Epinephelus moara胚胎发育及仔、稚、幼鱼形态进行了观察与研究，详细描述了各发育期的形态特征和发育时间。结果表明：1）在水温22±0.2℃、盐度30、溶氧7.8mg/L、pH 8.25的条件下，云纹石斑鱼的受精卵历时38h 17min开始孵化出膜。胚胎发育可分为受精卵、卵裂、原肠、神经胚和器官形成及出膜6个阶段，受精、胚盘形成、2细胞等28个时期。2）在水温23±1℃，盐度30±3，DO≥5mg/L，pH 8.0±0.5的海水中，培育至5d，卵黄囊完全消失，成为后期仔鱼；培育至27d，发育最快的云纹石斑鱼结束仔鱼期，进入稚鱼期；培育至65d，发育最快的稚鱼完成变态，成为幼鱼。胚后发育过程主要是根据卵黄囊、鳍膜、鳞片、体色及第1腹鳍棘与第2背鳍棘相对长度的变化分为仔鱼、稚鱼和幼鱼3个时期。其中仔鱼期又根据其卵黄囊的有无划分为前期仔鱼和后期仔鱼。

Abstract:

The embryonic and morphological development of larval, juvenile and young kelp bass Epinephelus moara were observed and studied. The morphological features and the developmental phases were described in great detail from fertilization to young fish. The results showed that the time period for embryonic development is 38h 17min at 22±0.2℃, salinity 30, DO 7.8mg/L, and pH 8.25. Based on the obtained data, six periods including 28 stages of E. moara embryo were described, which were cleavage, blastula, gastrula, neurula, organogenesis, and hatching period. After being reared for 5 days in the sea water at 23±1℃, salinity 30±3, DO≥5mg／L, pH 8.0±0.5, the yolk-sac of larvae disappeared and the late larval stage began; after 27 days, the faster growing larvae developed into juveniles; after 65 days, the faster growing juveniles completed metamorphosis and became young fish. The post embryonic development of E. moara was divided into larval stage, juvenile stage as well as young fish stage, based on the features of the yolk-sac, finfold, pelvic fin spine, second dorsal fin spine, scale and body color. Accordingly, the larval stage was further classified into early larvae and late larvae, according to the existance of the yolk-sac, respectively.