网箱养殖黄斑篮子鱼胚胎发育观察

Observation on embryonic development of cage-breeding Siganus oramin

在深水抗风浪网箱培育黄斑篮子鱼(Siganus oramin)亲鱼,选取性腺成熟的1+龄亲鱼进行打针催产并人工干法授精,将获得的受精卵在实验室孵化,观察并记录胚胎发育全过程。结果表明,网箱培育的黄斑篮子鱼亲鱼捕捞回室内水泥池,打针催产后其排卵授精行为仍具有严格的月历节律性;黄斑篮子鱼受精卵为沉性黏性卵,圆球形、卵膜光滑、卵质透明、多油球。卵径(584.6±8.64)μm,油球多个,大小不一,大油球直径(146.54±7.46)μm;在水温23.2~24.5℃、盐度32.5和p H 8.2的环境下,第39小时20分钟第一尾仔鱼孵化,第42小时10分钟全部受精卵孵化出仔鱼,积温925.28~996.45℃·h,胚胎发育过程可以分为胚盘期、卵裂期、囊胚期、原肠胚期、神经胚期、器官形成期、孵化期等7个阶段,包括26个发育时相。初孵仔鱼全长(1 912.54±105.25)μm,2.5日龄(孵化后第56小时)仔鱼开口,全长(3 030.36±80.97)μm。

The parent fish of Siganus oramin were bred in deep-sea anti-wave cage. We selected the 1＋ aged parent fish with mature sex glands for spawning artificially and dry insehation. The fertilized eggs obtained were incubated in laboratory for observation of the whole process of embryo development. The results show that the ovulation and insemination behavior of cage-breeding S.oramin still remained a strict rhythm of the calendar after being induced spawning in a cement pool. The mature zygote of S.oramin was heavy, sticky and round with multi-oil ball, and the egg membrane was smooth and ooplasm transparent. The diameter of zygote was （584.6±8.64） μm, and the maximum oil ball diameter was （146.54±7.46） μm. The first larvae hatch finished at 39th hour 20 min under 23.2–24.5℃ at salinity 32.5 and pH 8.2. All fertilized eggs completed incubation at 42nd h 10 min with accumulated temperature of 925.28–996.45℃·h. According to morphological characteristics, the process of embryonic development could be divided into seven physiological stages with 26 periods：blastoderm form stage, cleavage stage, blastula stage, gastrula stage, neural stage, organogenesis stage and hatching stage. The body length of newly hatched larvae was （1 912.54±105.25） μm; the larvae opened mouth at 2.5 dph （56 h after incubation） with total length of （3 030.36±80.97） μm.