达氏鳇胚后发育的形态观察

样本系黑龙江野外采集的达氏鳇(Huso dauricus)亲体经人工受精后孵出的子一代,对刚出膜的仔鱼0日龄,体长(12.08±0.68) mm]到早期稚鱼60日龄,(129.21±7.69) mm]的胚后发育形态进行了观察.从形态发育上看来,达氏鳇仔鱼的胚后发育可分为2个时期:早期仔鱼阶段,即从刚出膜(0日龄)到初次开口摄食(9日龄);晚期仔鱼阶段,即从初次开口摄食到各器官发育基本完成,体透明特征消失,鳍褶和颌齿彻底消失(50日龄),之后进入早期稚鱼期.早期仔鱼的形态发育和分化明显较晚期仔鱼和稚鱼快,运动、呼吸、感觉和消化等器官在此期间发育与分化快速同步协调,且速度快,使得仔鱼获得避敌与摄食能力,提高了成活率.晚期仔鱼发育主要表现为各骨板的分化和完善,鱼鳍游泳器官功能的进一步强化,鳔的发生和发育,表明此阶段游泳和躲避敌害能力进一步增强.

Morphological observation of postembryonic development in Kaluga, Huso dauricus

We documented the postembryonic development ina first filial generation of Kaluga, Huso dauricusbased on microscopic observation. The parent Kaluga were captured from the Amur River and mated. We documented development between the new born prelarval stage 0 day after hatching (dah), (12.08 ± 0.68) mm] and the early juvenile stage 60 dah, (129.21 ± 7.69) mm]. The development was divided into two phases, the prelarval stage between hatching and first feeding(0-9 dah), and the postlarval stage between the initiation of external feeding and completion of organ development, when the skin becomes opaque and the fin folds anterior to the anus and oral teeth have disappeared(50 dah). The morphological development and differentiation were more rapid in prelarvae than in postlarvae. During the prelarval stage, a range of swimming, respiratory, sensory, and feeding organs developed rapidly. Rapid development of these functional organs presumably enables prelarvae to forage and avoid predators, thereby increasing the likelihood of survival. Further differentiation and development of bone plates, further development of fins, and appearance and development of the swim bladder occurred during the postlarval stage. The changes occurring during this latter stage likely lead to further improvements in the ability of fish to forage and avoid predators.