in a way similar. Centropages mcmurrichi, which is quite 

 typical of this group, formed maximal conglomerations in the 

 eastern Chirikov basin, the Bering Strait, and in the southern 

 Chukchi Sea, where its total number reached 5,500 ind/m^ 

 (Fig. 12). 



Fig. 12. Distribution of Ceniwpages mcmurrichi in the northern Bering and 

 southern Chukchi Seas. 



Distribution of Total Number and Biomass of 

 Mesozooplankton 



In the central part of the Bering Sea at the eastern boundary 

 of deep- water and shelf regions (East Polygon), the amount of 

 the total number of mesozooplankton varied from 0.9 to 

 2.2x 10' ind/m- (averaging 2. Ix ICind/m-XFig. 13). The low 

 level of the index was attributed to the outer shelf region where 

 the depth increased to 140 m. The highest total numbers were 

 found at deep-sea stations of this polygon (about 3,000 m). 

 Total biomass of the community at these stations varied within 

 a not significant range of 25.8-31.4 g/m- (an average of 

 29.0 g/m-) (Fig. 14). 



Total number of mesozooplankton at the South Polygon 

 reached a somewhat lower value than that of the East Polygon 

 — 1.8 X IC" ind/m"; biomass was at the same level — 

 28.7 g/m- average. In the northeastern Bering Sea, abundance 

 of the mesozooplankton community was considerably lower 

 than those of central and southern regions (Fig. 1 3). The index 

 varied from 1 18 to 857 x 10' ind/m-. Relatively numerous 

 conglomerations of organisms were found in the epipelagic 

 zone of southern and northern parts of the study area. 

 Distribution of total biomass of animals was the same as the 

 distribution of total abundance. At the same time, the highest 

 biomass was in the northwest deep-sea region and totaled 



© 



24 







15 



o 



o 



32 



o 



fc 







22 



© 

 35 



® 

 19 







9 



o 



Fig. 1 3. levels of total number of mesozooplankton at South and East Polygons 

 and in the northwest part of the Bering Sea. 



Fig. 14. Levels of total biomass (wet weight) of mesozooplankton at South and 

 East Polygons, and in the nortwest part of the Bering Sea. 



65 .4-82.9 g/m'; this is the highest value found during the cruise 

 (Fig. 14). 



Variability of abundance of the mesozooplankton in the 

 Chirikov basin was enormous. In the eastern part of this region, 

 abundance was much higher than in the western part — from 

 2,712,000 to 1 82,000 ind/m- (Fig. 15). Total biomass variation 

 was not significant, still in the southern part of the region, they 



168 



