Table 3. Mean annual and mean maximal values of zooplankton biomass 

 (mg/m3) through entire thickness of water in the southeastern part of the 

 Barents Sea (Zelickman, Kamshilov, 1960, modified). 



Biomass 1951 1952 1953 1954 1955 1956 1957 1958 



Mean annual 100 23 45 129 71 67 60 48 

 Mean maximal - - 287 300 291 93 45 337 



magnitude (Lie, 1968b), while fluctuations in the 100-600 m layer did not 

 exceed 0.05 ml/m^ (Lie, 1968b). The number of mature euphausiids of 

 T hysanoessa i nermis and T. raschii (by trawl net collections) in the 

 Barents Sea in 1954-19752 varied by a factor of 3-4 (Drobysheva, Soboleva, 

 1976). Five-year annual collections in Chupa Bay (White Sea) showed 

 that the zooplankton population in the 0-60 m layer was approximately 10 

 times as numerous in July as in January, the biomass being about 4-5 

 times greater (Prygunkova, 1974). 



The data presented above indicate that zooplankton of the Arctic 

 community, in spite of significant perturbations in climate and the 

 hundred-year pressure of anthropogenic factors, has retained a rather 

 stable mean level of production, indicating clear homeostasis of the 

 System. Consequently, Arctic plankton can withstand significant stress, 

 while retaining its stability and integrity. The matter is quite different 

 with the nekton. As a result of fishing, the economically valuable 

 species which previously predominated have greatly decreased in number, 

 their niches being immediately occupied by other plankton consumers, 

 less valuable from the human point of view. Thus, the herring have been 

 replaced by poutassou, the feeding areas of the cod, pollock and haddock 

 have been partially occupied by the Arctic cod and capelin (Sonina, 1969. 

 1973; Ponomarenko, 1968). The zooplankton population can drop irreversibly 

 only in response to very basic changes in the substratum (e.g., an increase 

 in pollution) and (or) human interference in the interrelationships of the 

 basic units of the ecosystem. 



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