Samples from twelve consecutive cruises in 1959 were analyzed to determine the distribution patterns of abundance and seasonal dynamics of major taxa in the Bohai Sea except copepoda.rn 1) Coelenterata: The seasonal changes of medusae showed bimodal with the first peak in February and the second in June. The common species included Rathkea octopunctata, Phialidium chengshanense, P. discoidum, Eirene ceylonensis, Liriope tetraphylla, Proboscidactyla flavicirrata, Muggiaea atlantica. Most of them were neritic species and they mainly distributed in the coastal areas. Rathkea octopunctata peaked in February and Eirene ceylonensis, Phialidium chengshanense, P. discoidum, Eirene ceylonensis peaked in summer.rn 2) Cladocera: The most common species was Penilia avirostris. Penilia avirostris was a typical neritic species and mainly distributed in coastal waters in Laizhou Bay. It peaked in June with an average density of 151.1 ind./m3 and the highest abundance is 7855 ind./m3.rn 3) Mysidacea: Gastrosaccus pelagicus, Acanthomysis longirostris, Acanthomysis hwanhaiensis were common species. Gastrosaccus pelagicus was abundant in late autumn and Acanthomysis longirostris correlated little with temperature with three peaks in spring, summer and autumn respectively. These two species were both neritic species and distributed in coastal waters.rn 4) Appendicularia: Oikopleura longicauda was the most abundant species and its seasonal dynamics showed bimodal with the first peak in May and the second in August. In most of the year, it mainly distributed in coastal waters.rn 5) Chaetognatha: Sagitta crassa was one of the most important carnivorous species and it was abundant in September. One of the reproductive seasons occurred in June and the other occurred in late autumn.rn 6) Amphipoda: Themisto gracilipes was one of the most common species in the Bohai Sea. It was most abundant in June and July. Its distribution closely associated with salinity and it mainly occurred in center waters with high salinity.rn 7) Larvae: 17 taxa larvae were recorded. Among them, Spoinidae larva, Nauplius, Gastropoda larva and Lamellibranchia larva were the most common groups.Spoinidae larva and Nauplius were most abundant in April and Grastropoda larva and Lamellibranchia larva were most abundant in late summer and autumn. Those larvae were neritic species and mainly distributed in coastal water.%用1959年全国海洋普查中网浮游动物标本，分析渤海水母类、枝角类、糠虾、毛虾和幼虫等的数量分布和季节变化。结果表明，水母类以近岸低盐种为主，主要出现在莱州湾、渤海湾和辽东湾近岸水域。冬季出现的种类较少，优势种为八斑芮氏水母；夏季种类较多，优势种为半球杯水母和嵊山多胃水母等。鸟喙尖头FDA5为近岸高温低盐种，主要出现在莱州湾，数量在6月份达到最大值。箭虫是渤海主要肉食性种类之一，其数量高峰期出现在9月份。长住囊虫的季节变化呈双峰型变化，第1次数量高峰出现在5月份，第2次数量高峰出现在8月份。该种大部分时间主要分布在莱州湾、渤海湾和辽东湾近岸水域。渤海出现的糠虾有长额刺糠虾和漂浮囊糠虾，其中长额刺糠虾受温度的影响较小，在春、夏、秋各有一个数量高峰；漂浮囊糠虾在秋末数量明显增加。这两种糠虾主要分布在渤海湾和辽东湾近岸水域。三叶针尾涟虫属于低温种类，主要出现在秋季和冬季。细长脚FDC5属夏季高温种，在6、7月份数量较高。该种的分布受盐度影响比较大，主要出现在受黄海海流影响的高盐水域。数量较大的幼虫有桡足类的六肢幼体、多毛类海稚虫科的幼体、双壳类幼体和腹足类幼体。其中桡足类六肢幼体和海稚虫科的幼体在5月份出现较多，腹足类幼体在6、7月份数量较高，双壳类幼体在8月份数量较高。
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