of the population from the Labrador Basin, which communicates broadly with 

 the adjacent waters of the open North Atlantic. The North Atlantic Current 

 may carry these crustaceans to the northeast and even through the Faeroe- 

 Shetland Channel into the southern area of the Norwegian Sea. On the other 

 hand, a portion of the population of C. finmarchicus from the Norwegian Sea 

 is carried along with the East Iceland Current into the open North Atlantic 

 and subsequently may be carried to the south and west. Thus, these two, 

 large, independent populations of this species may be interconnected by 

 means of a third population, less numerous and more or less dependent on 

 the first two. We should keep in mind the fact that, in spite of the 

 predominance of transport water in the northeastern direction, the open 

 portion of the North Atlantic which we are considering does have its own 

 cyclonic system of circulation of water masses, though it is highly complex 

 and not clearly expressed. Therefore, the population of C^. finmarchicus 

 which inhabits this area cannot be considered totally dependent. In part, 

 it may be drawn into the circulation or may be delayed for an indefinite 

 period in any portion of the circulation due to eddies in the current, 

 e.g., in the region of the Irminger Sea. 



In zones of mixing of subarctic waters with the waters of the Polar 

 Basin (Davis Strait, northeast of the Norwegian Sea), C^. f inmarchicus s. str. 

 is found together with its close relative C. gl acial is and with £. hyperboreus - 

 species which occupy the Arctic area, but penetrate with streams of cold 

 water into the temperate latitudes (Jaschnov, 1963, 1970). To the south of 

 the Faeroe-Shetland Channel, in the northeastern Atlantic, C. finmarchicus 

 s. str. is found together with another relative species--£. hel golandicus 

 (Marshall, Orr, 1955; Jaschnov, 1961). This species, a part of the 

 Lusitanian faunistic complex, is carried into the Norwegian Sea and the 

 nrothwest Atlantic only sporadically. In contrast to the species we have 

 mentioned, C. finmarchicus s. str. is a true boreal species, endemic for the 

 temperate regions of the Atlantic Ocean (Jaschnov, 1961, 1970). 



Among other species of copepod filter feeders, in the boreal waters 

 of the North Atlantic, P seudocalanus elongatus and £. minutus are present 

 in great quantities. The former (smaller) species is particularly numerous 

 in shallow waters over the shelf; the latter is found primarily in the 

 oceanic zone and plays a significant role in the pelagic communities of 

 the Labrador Basin (Pavshtiks, 1969; Kielhorn, 1952) and the Norwegian Sea 

 (Pavshtiks, Timokhina, 1972; Wiborg, 1954). These species are morphologically 

 difficult to distinguish, and their biology has not been sufficiently 

 studied. Their reproductive season is quite extended: practically all 

 summer, in addition to the mature individuals of both species, the plankton 

 contains their nauplial and early copepodite stages. Obviously, during 

 the year £. e longatus and £. minutus breed several times, but different 

 breeding periods are difficult to distinguish. The greatest number of 

 Pseudocalanus in different years in the North Atlantic may occur in 

 different months during the spring, summer or fall; in the Norwegian Sea 

 it is most frequently observed in the summer or fall (Gruzov, 1963; Wiborg, 

 1954, 1955). In contrast to the Norwegian and Labrador Seas, in the open 

 North Atlantic, Pseudocalanus spp. are not a significant fraction of the 

 plankton, being usually replaced by more thermophilic and oceanic species 



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