中文摘要：

在水温（20．5±1．0）℃的条件下，采用实验生态学的方法，对美洲西鲱（Alosasapidissima）仔鱼在饥饿状态下的生长、形态、不可逆点（PNR）及仔、稚鱼期的摄食节律进行了研究，旨在阐明美洲西鲱早期发育过程中的摄食规律和特点。实验结果表明，美洲西鲱初孵仔鱼全长（7．45±0．15）mm，体质量为（2．15±0．03）mg，卵黄囊体积为（5．99±0．13）mm^3，第5日龄，仔鱼卵黄囊被完全吸收。对照组仔鱼全长及体质量随着卵黄囊的消耗、外源性营养的建立逐渐增加；饥饿组仔鱼自6日龄开始，全长及体质量开始呈现负增长，至10日龄全部死亡。美洲西鲱初孵仔鱼初次摄食时间在3日龄，摄食率为46．67％，5日龄摄食率达到最大为89．29％，PNR发生在7～8日龄，综上所述，美洲西鲱仔鱼最佳投喂时间应在2-3日龄。美洲西鲱仔、稚鱼摄食节律研究表明，美洲西鲱早期仔鱼（4日龄）昼夜摄食高峰出现在14：00，平均摄食量达到0．14mg；晚期仔鱼（17日龄）在10：00和14：00出现较高的摄食量，分别为0．92和1．36mg；28日龄稚鱼在10：00、14：00和18：003个时间段维持着较高的摄食量，摄食量分别为1．77、2．45和1．55mg，属于典型的白天摄食类型，且随着仔稚鱼的生长发育，摄食高峰期逐渐延长。美洲西鲱仔、稚鱼各阶段的日摄食率分别为20．08％（4日龄）、29．48％（17日龄）和12．41％（28日龄），可将其作为美洲西鲱日投喂量的参考标准。

英文摘要：

In order to better understand the feeding characteristics of Alosa sapidissima at the early development stage,the effects of starvation on growth and morphology, the point of no return （PNR） of A. sapidissima larvae, and the feeding rhythm of A. sapidissima larvae and juveniles were researched by experimental ecology approach at the water temperature of （20.5 ±1.0） ℃. It has been clearly described that newly-hatched larvae were （7.45 ± 0.15 ）mm in total length （TL）, （2.01 ± 0.06 ）mg in body weight（BW） and the yolk sac was（5.99 ± 0.13 ）mm^3 in volume. 5 days after hatch（ DAH）, the yolk sac of A. sapidissima larvae was absorbed completely. Both TL and BW of control group increased gradually with the consumption of yolk sac and the establishment of exogenous nutrient. In contrast, the TL and BW of the starved larvae started to decrease from 6 DAH, and all the starved larvae died at 10 DAH; The first feeding time of A. sapidissima larvae was 3 DAH,the feeding rate reached 46.67% ,the higtest feeding rate was 89.29% in 5 DAH,and the PNR was 7 -8 DAH. According to the yolk sac absorption and PNR,the the optimal time of initial feeding should be 2 - 3 DAH. The feeding rhythm of A. sapidissima larvae and juveniles exhibited that the feeding peak of early stage larvae（4 DAH）appeared at 14：00, and the feeding amount reached 0.14 mg; the feeding peak of late stage larvae（ 17 DAH）was at 10：00 and 14：00, and the feeding amount was 0.92 mg and 1.36 mg,respectively;the juvenile at 28 DAH reached three feeding peaks at 10：00,14：00 and 18. 00,and the feeding amount was 1. 77,2. 45 and 1. 55 mg, respectively. Therefore, A. sapidissima was typically feeding only in daytime, and the feeing peak period was gradually prolonged with fish growth. The result of daily feeding situation of A. sapidissima showed the feeding rate in daytime was 20.08% （4 DAH）, 29.48% （17 DAH）and 12.41% （28 DAH） ,which could be a reference for A. sapidissima daily feeding.