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. 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 ...