of the genera Paracalanus , Ctenocalanus and C lausocalanus , which, in 

 spite of their small size, sometimes represent a significant fraction of 

 the zooplankton biomass (Kanaeva, 1962). In the Labrador Basin and the 

 Norwegian Sea, P aracalanus and C lausocalanus are not numerous. 



Yet another small species of copepod reaches significant numbers in 

 the boreal waters of the North Atl antic- -M i crocal anus p usillus . Information 

 on its life cycle and the nature of its feeding is almost totally 

 absent from the literature. It is assumed (S. M. Marshall, 1949) that 

 M. pusillus feeds on flagellatae. 



Among the copepods with mixed diet, Metridia lucens is most important 

 in the North Atlantic, being ubiquitous, although it is most frequently 

 encountered in the southern portion of the boreal area: in the region 

 of the Flemish Cape Bank, in the open waters of the boreal Atlantic, in 

 the southern part of the Norwegian Sea (Kanaeva, 1963; Semenova, 1964; 

 Timokhina, 1968). However, this species never represents a great biomass 

 and, in this respect, is quite different from the similar Far Eastern 

 species M. p acifica , which may form significant concentrations. The 

 breeding season of M. l ucens in the North Atlantic is extended: The 

 nauplii and juvenile forms are encountered throughout the year, though 

 most numerous in spring and fall; the species achieves its highest 

 number in late summer (Gruzov, 1963). Another species of the genus--M. 

 longa --is an Arctic one, although it can penetrate far into the temperate 

 regions with cold currents, where it usually is seen together with C. 

 j lacial is and C^. hyperboreus . In mixed waters in the northern part of 

 the boreal area, M. T onga is quite common and, due to its large dimensions, 

 may represent a significant fraction of the zooplankton biomass (Pavshtiks, 

 1964; Timokhina, 1968). In the open waters of the boreal Atlantic, in the 

 southern portion of the Labrador and Norwegian Seas, Pleuromamma robusta 

 is rather common, and sometimes one also sees P^. abdominal is , P. x iphias , 

 P. boreal is and £. gracil is , which are common in the subtropics and reach 

 the southern portion of the boreal area with the North Atlantic Current. 



Among the other euryphagous copepods for the boreal Atlantic, we should 

 note Scolecithricel la minor . The small euryphagous calanoids form a 

 unique complex: Acartia clausi , Centropages hamatus , £. typicus , Temo ra 

 I pngicornis . They are found primarily in the neritic zone, but extend 

 widely into the central waters of the Labrador Basin and the Norwegian 

 Sea as well. Their numbers may be relatively high, particularly in late 

 summer-early fall, but due to their small size they usually are not 

 significant in the total mass of plankton. Their breeding period is 

 extended, occurring primarily in the spring and summer, they are rare in 

 the open waters of the North Atlantic, 



There are not many abundant species of predaceous copepods in the 

 boreal area of the Atlantic. The most important one is P areuchaeta 

 norvegica , which, due to its large size and ability to form concentrations, 

 plays a significant role in the pelagic community and represents an important 

 component in the nutrition of the planktophagous fish. Furthermore, P. 

 norvegica , extending over a broad range of depths, is frequently eaten by 



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