Oecological observation especially on the algal distribution in brackish lakes Nakano-umi and Shinzi have been made. The distribution of macroscopic algae are gradually paralleled with a gradual dropping out of chlorinity range of this region. These regions are characterized by four patterns of algal distribution. The patterns and each of the indicators are shown in the Fig. 1. A.
The proportion of diminuation of specific component in Rhodophyceae is more remarkable than the other systematic groups. The distribution of fresh-water alga Compsopogon Oishii Okam. is reported as a newly found locality in the coastal region of the Japan Sea.