Number of specimens . 



Calanus flnmarchicus IV and V stages 

 Oithona similis 

 Oithona atlantica 

 Pseudocalanus elongatus 

 Eukxohnia hamata 



4 

 4 

 4 

 3 

 1 



Depth 

 meters 



Autumn 



Figure 2. Chart of the distribution of the main planktonic organisms in the water during 



the various biological seasons. Spring -green bloom (I) and the reproduction of 

 crustaceans . Their eggs and nauplii are in the plankton . The development of 

 diatoms (H) and the growth of young Calanus, of euphausids and others . The 

 descent of the euphausids that have spawned and the dying of the green bloom 

 (I^). Summer - the rapid development of diatoms (11^ and 11*^). Fat, red Calanus 

 and the young of euphausids . Diurnal vertical migrations of Calanus . Autumn - 

 mass development of jellyfish and Ctenophora. Descent of Calanus and of other 

 organisms into the deep. Formation of the "winter stock". 



In certain places where there are depressions in the sea bottom, small concentrations of planktonic 

 organisms, the so-called "winter stock", can be observed. 



At the end of winter, sexually mature Euphausiacea artd also individual specimens of Calanus 

 flnmarchicus that are getting ready for spawning leave the bottom layers. In the southern regions 

 of the Norwegian Sea they begin their diurnal vertical migrations . 



109 



