100 BIOLOGY OF THE SEAS OF THE U.S.S.R. 



connecting Vaigach Island with Stur-fjord in Spitsbergen, from the work of 

 V. Jashnov (1939), B. Manteufel (1939) and M. Kamshilov (1956, 1957). 

 The quantitative and qualitative distribution of plankton and its changes with 

 depth are given in Fig. 36 for the Kola meridian (33° 30') northwards to 

 76° 30' latitude in June, August and December of 1929 and 1930. A considera- 

 tion of these three cross sections leads to some very important conclusions.* 



The marked preponderance of Calanus finmarchicus over all the other 

 forms is obvious. Secondly a comparison of the cross sections A and В reveals 

 that in the southern part of the Sea the mass development of Calanus fin- 

 marchicus occurs in the beginning of the summer, and to the north of 72° or 

 73° in the autumn. Also there stands out sharply the high density of popu- 

 lation in the upper levels in summer and in the lower levels in winter. The 

 middle layers of water are the most scantily populated. 



Zooplankton biomass decreases as we move from the open parts of the 

 sea up into the inlets {Table 34). 



Table 34 



Large bays corn- 

 Area Open parts of municating freely Inlets more or less 

 Barents Sea with Sea isolated from Sea 



Mean zooplankton 

 biomass, mg/m 3 140 49 43 



B. Manteufel gives a number of interesting data on the qualitative and 

 quantitative distribution of zooplankton in the southwestern part of the 

 Barents Sea. The amount of zooplankton sometimes reaches 8 to 9 g/m 3 but 

 usually it varies from 200 to 2,000 mg/m 3 , increasing during the summer. 



Generally speaking, the amount of zooplankton in this southwestern area 

 is only slightly below that of the northern parts of the Atlantic Ocean where 

 plankton is especially abundant. M. Kamshilov (1957) gives quantitative 

 data for zooplankton from the southern part of the Barents Sea for July 1953. 

 In the littoral zone of the Murman coast two centres of mass development 

 of plankton have been observed — the northwest one of Calanus and the 

 southeast one composed mainly of Cirripedia larvae. The shoaling of herring 

 in this region is conditioned apparently by the mass development of plankton 

 in the littoral. 



A seasonal census of plankton in the Barents Sea carried out by V. Jashnov 

 (1940) permitted him to approximate to a solution of the problem of its 

 annual production capacity. Using A. Vinogradov's data on the chemical 

 composition of plankton consisting of Calanus finmarchicus (Table 35), 

 Jashnov gives an estimate of the chemical composition of the Barents Sea 

 plankton as a whole, in millions of tons (Table 36), expressing the total 

 production of the Sea by the amount of food required by the whole mass of 



* Total plankton biomass is represented by the area of the circle, while the biomass of 

 different plankton components is shown by sectors. 



