太平洋鳕(Gadus macrocephalus)亲鱼驯化培育与早期发育特征

Domestication of Wild Broodstock and Early Development of Pacific Cod (Gadus macrocephalus)

中文关键词: 太平洋鳕  亲鱼驯化  胚胎发育  早期发育

英文关键词: Gadus macrocephalus  Broodstock domestication  Embryogenesis  Larval development

中文摘要:

      采捕山东威海外海黄海海域的太平洋鳕(Gadus macrocephalus)亲鱼进行驯化和培育，在人工条件下成功驯化存活野生亲鱼49尾，经短期促熟培育后，通过人工授精方式获得了多批次受精卵。对胚胎和早期仔鱼发育过程进行了观察，详细描述了从受精卵到早期仔鱼各发育时期的形态特征。结果显示，太平洋鳕成熟卵子为沉性卵，圆球形，卵径为0.9–1.1 mm，无油球。胚胎发育分为5个时期，分别为卵裂期、囊胚期、原肠胚期、神经胚期和器官形成期。在水温为9–10℃、盐度为27–29的海水中孵化，受精卵历时312 h 30 min孵化出膜。初孵仔鱼全长为(3.85±0.12) mm，6日龄仔鱼开口，肛门与外界相通，进入混合营养期。8日龄仔鱼卵黄囊消耗殆尽，开始进入外源性营养阶段。仔鱼开口饵料为轮虫(Rotifer)，12日龄开始摄食卤虫(Artemia saline)无节幼体。6日龄仔鱼鳔原基形成，16日龄鳔充气成为亮泡状。12日龄仔鱼形成肠道第1个生理弯曲，22日龄仔鱼第2个肠道生理弯曲形成。研究结果可为太平洋鳕亲鱼驯化培育和苗种培育提供基础资料。

英文摘要:

      Pacific cod (Gadus macrocephalus) is a commercial potential species for marine fish aquaculture. The present study used a wild population of Gadus macrocephalus that was captured from the open sea of Weihai (Yellow Sea region). Under captivity, 49 wild individuals survived and acclimated to broodstock rearing conditions. Shortly, 15 batches of fertilized eggs were collected. Embryogenesis and early larval development of G. macrocephalus, including morphological features and development time, were described. G. macrocephalus spawned demersal and slightly adhesive eggs. Eggs were almost spherical and had no oil globules with diameter about 0.9–1.1 mm. The embryonic development of G. macrocephalus was divided into five stages, namely cleavage stage, blastula stage, gastrula stage, neurula stage as well as organogenesis stage. Embryos hatched out after 312 h 30 min in the sea water when the temperature was 9–10℃. The total length of newly hatched larva was (3.85±0.12) mm．Larva opened mouth at 6 days post hatching (dph) and started exogenous nutrition (first-feeding) stage. The yolk was completely absorbed at 8 dph. Primordial swimming bladder appeared at 6 dph and was filled with air at 16 dph. The first and second intestine physiological curvature formed at 12 dph and at 22 dph, respectively. This study provides the important baseline reference for broodstock management and larviculture of G. macrocephalus.