THE SEA OF JAPAN 765 



Copepoda and Euphausiaceae are very important in the diet of plankton- 

 eating fish, and in this respect herring has many rivals. In their turn Euphau- 

 siaceae and Chaetognatha consume very large numbers of Copepoda. It is 

 remarkable that the Pacific Ocean herring {Clupea harengus pallasi), which 

 lives in the northern part of the Sea of Japan, has the same diet as the Atlantic 

 herring of the Barents Sea (Thysanoessa inermis, Th. raschii and Calanus 

 finmarchicus), but in the Sea of Japan it adds Sagitta elegans as a further 

 component of its diet. 



The flora of the bottom-living macrophytes of the Sea of Japan has been 

 investigated by the Soviet and Japanese workers E. Zinova (1928-54), 

 G. Gail (1930, 1936), T. Shchapova (1948, 1957), Miyabe (1908), K. Oka 

 (1907-34) and J. Tokida (1957). Three hundred and seventy-nine species of 

 bottom-living macrophytes of the Sea of Japan are listed in Table 310. 



T. Shchapova has investigated the littoral flora of the Soviet's Primor'e for 

 a number of years (from 1948). The exclusively littoral forms of the bottom 

 flora (including the uppermost horizon of the sublittoral up to 1 m) compose 

 only 25 per cent of the total, e.g. about 72 to 74 species. The marine flora of 

 the Primor'e does not contain Arctic or tropical organisms. Arctic-boreal 

 forms are predominant in the northern part and boreal ones in the southern. 

 Pylaiella littoralis and Dictyosiphonfoeniculaceus are most characteristic of the 

 first group ; Langsdorfii sp., Sargassum miyabei, Cystoseira crassipes, C. hako- 

 datensis, of the second. They are mainly endemic organisms of the northern 

 part of the Pacific. Apart from them the sea-weeds of the Sea of Japan con- 

 tain also some amphi-boreal species such as, for example, Halopteris scoparia, 

 Leathesia difformis, Ralfsia clavata, Colpomenia sinuosa, and some bipolar 

 ones — Scytosiphon lomentarius, Ilea fascia. Many organisms are distributed 

 on both sides of the Pacific ; on the other hand many of them are endemic 

 forms of the Asian coast — Nemacystus decipiens, Stschapovia flagellaris, 

 Cystoseira crassipes and others. The dominant species of the littoral and of the 

 upper horizon of the sublittoral are the following, which are endemic to the 

 northern part of the Pacific Ocean : Heterochordaria abietina, Pelvetia wrightii 

 f. babingtonii, Coccophora langsdorfii, Sargassum miyabei, Cystoseira crassipes, 

 C. hakodatensis. The most profusely developed Laminaria of the Primor'e 

 are Laminaria japonica, L. den tiger a, Alaria crassifolia, A. fistulosa, which 

 also are endemic to the Pacific Ocean. 



