犬齿牙鲆胚胎及仔、稚、幼鱼形态发育观察

Embryonic and larval morphological development of Paralichthys dentatus

犬齿牙鲆（Paralichthysdentatus）卵为端黄卵，受精卵浮性，卵径950～1100p．m，油球径200～225btm。在水温20．5～22．0℃，盐度33条件下培育，受精后1h20min进入卵裂期，6h10rain进入囊胚期，11h20rain进入原肠胚期，19h10rain发育到胚孔封闭期，胚体形成，26h50min尾芽出现，33h35min心跳开始，48h10rain开始孵化出仔鱼。初孵仔鱼平均全长2．59mm±0．02mm，在培育水温为17．0～21．0℃，盐度24～34条件下，胚后发育时序为：1日龄～9日龄为仔鱼前期，10日龄平均全长5．52mm±0．05mm，卵黄囊和油球完全吸收进入仔鱼后期；40日龄平均全长20．82mm±0．67mm，各鳍鳍条发育形成进入稚鱼期：65日龄平均全长41．13mm±0．88mm，全身鳞被完整进入幼鱼早期。

The eggs of summer flounder were telolecithal egg, and fertilized eggs were buoyant. The average di- ameter of eggs was 950-1 100 μm. Radius of oil globule was 200-225μm. The egg was hatched at water tempera- ture 20.5-22.0℃ and salinity 33. The embryos entered cleavage stage by 1 h 20 min after fertilization, entered the blastula stage by 6 h l0 min, entered the gastrula stage by 1 lh 20min, developed into the blastopore closure stage, embryo was formed. Tail bud appeared by 26h 50min, the heart beat began by 33 h 35 min, and larvae were hatched by 48 h 10 min. The average length of newly hatched larva was 2.59 mm±0.2 mm. At the cultivation temperature of 17-21℃, salinity 24-34, the postembryonic development timing sequence was： the fish of 1 day to 9 days after hatching were prelarva. The average length of 10 days fish was 5.52 mm±0.05 mm, yolk sac and oil globule were absorbed completely, and the fish entered the postlarvae stage. The average length of 40 days fish was 20.82 mm±0.67 mm, fin rays form, the fish entered the larval stage. The average length of 65 days fish was 41.13 mm±0.88 ram, the whole lodicules developed completely, the fish entered early juvenile stage.