This same community includes Euphausia pacifica , encountered in 



the Sea of Okhotsk primarily near the Kurile Islands (up to 1000 mg/m3), 



and in the central portion of the sea only in very small numbers during 



the period of greatest warming of the surface waters; apparently, it 

 does not breed in this area. 



The zone occupied by the neritic community is located along the 

 shores of the sea in a narrow strip extending along the northern shallow 

 water zones. This community includes larvae of benthic invertebrates and 

 neritic holozooplankton, consisting primarily of cold-water species. 



Japan Sea . The Japan Sea is distinguished by the diverse composition 

 and great variety of its plankton communities. 



Among the copepods, Pseudocalanus elongatus , and particularly 

 Calanus glacialis . are very important, encountered in the greatest numbers 

 in the southern portion of the Tatar Strait, extending to the south along 

 the continent with the cold Primorye Current as far as the shores of 

 Korea (Meshcheryakova, 1960). 



The community of the southwestern Sakhalin waters includes a number 

 of subtropical, in summer even tropical species and, at the same time, 

 some northern species (Ponomareva, 1954). A few individuals of the 

 Okhotsk Metridia ochotensis reach this area through La Perouse Strait. 



In the western portion of the sea, the communities of Possiet and 

 Amur Bays are characteristic (Brodsky, 1957). In Possiet Bay, representa- 

 tives of subtropical and even tropical fauna are encountered; this 

 warm-water community populates the waters of the coast of Korea, along 

 the eastern shore of which a branch of a warm current flows (Uda, 1934). 

 The community of Amur Bay differs from the Possiet community in that it 

 includes no tropical species. 



In the open portion of the sea, there are two communities: the 

 northern and southern communities, with their boundary at approximately 

 40°rNl. Of course, the position of this boundary varies from season to 

 season and from year to year, depending on the pulsations of the currents. 

 The 40th parallel is the boundary between the boreal and subtropical plank- 

 tonic fauna. 



The plankton of the Japan Sea is quantitatively rich, the biomass 

 of plankton in the open portion of the sea reaching 800 mg/m^, along 

 the coast as high as 2000 mg/m3. The biomass consists of calanids 

 (C^. plumchrus , C. pacificus , and in the north C. glacialis as well) and 

 euphausiids (1T[. inermis , Th. longipes , and in the north also Th. raschii , 

 in the south-- Euphausia pacifica ). In some areas, Parathemisto japonica 

 plays an important role in the biomass of the plankton. 



Northern portion of the Pacific Ocean and Bering Sea . In the Bering 

 Sea, five distinct plankton communities can be differentiated (Brodsky, 

 1955; Vinogradov, 1956). The southern oceanic community is quite similar in 

 its specific composition to the oceanic community of the extreme northern 



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