西伯利亚鲟(F_2)胚后发育的形态观察

Morphological observation on postembryonic development of Siberian sturgeon Acipenser baeri(F_2)

对人工养殖西伯利亚鲟(F2)仔鱼的胚后发育形态进行了观察,从仔鱼刚出膜[0日龄,(9.16±0.21)mm]开始一直观察到早期稚鱼阶段[53日龄,(87.12±1.92)mm]。从形态发育来看,西伯利亚鲟仔鱼的胚后发育可以分为2个时期:早期仔鱼,即从刚出膜(0日龄)到初次开口(9日龄)摄食;晚期仔鱼,从开口摄食至器官发育基本完全(37日龄);以后进入早期稚鱼期。早期仔鱼期的形态建成与分化明显地比晚期仔鱼和早期稚鱼快,其中,早期仔鱼的感觉、摄食、呼吸、游泳等器官快速分化;晚期仔鱼,主要表现为各骨板的分化和完善,当仔鱼在形态上完成向成鱼转变时,表示进入了早期稚鱼期。西伯利亚鲟胚后发育的观察结果显示,发育的早期阶段各器官协调并快速发育,感觉、摄食、呼吸、游泳等器官的出现和完善,使仔鱼在短时间内具备了躲避敌害和摄食的能力,其生存能力大大提高。

Siberian sturgeon Acipenser baeri is one of the most popular fresh water aquaculture species in China. Artificial spawning of this species has succeeded. In order to provide information that may help with the improvement of fry rearing techniques, the morphological observation during postembryonic development of Siberian sturgeon Acipenser baeri （F2 ） were studied under rearing conditions. Newborn prelarval （0 day age） [ mean ± SD full length （FL） （9.16 ±0.21 ） mm]was conducted till the age of 53 days （87. 12 ± 1. 92 ） mm. According to morphological development, postembryonic development of Siberian sturgeon was divided into two different phases, the prelarval stage between hatching （0 day age） and first feeding （9-day age ）, and the larval stage between the initiation of external feeding and metamorphosis （37-day age ）. During the prelarval stage, the differentiation and morphological development of respiratory, swimming, sensorial and feeding systems were very intense, while the larval period as characterized by the development of dorsal, lateral and ventral rows of scuta. Morphogenesis and differentiation were more intense during the prelarval than larval and early juvenile stages. Such abrupt changes on growth patterns were related with improvement on respiration, feeding and swimming ability. Rapid development of those functional systems helped larvae escape from predators and get external food efficiently, which contributed to its survival. For the improvement of artificial fry rearing technique, specific conditions should be provided in time which depend on the early life stage growth patterns, so that important organs might have priority to develop normally and survival rate of early life stage might increase.