Calanus finmarchicus. The amount of oxygen used by this crustacean in the 

 adult state is assessed on the basis that 1,000 specimens require 0-33 m 3 /hour 

 in the summer. 



On the other hand, knowing the chemical composition of Calanus fin- 

 marchicus, it may be calculated that 222 g of oxygen is required for the oxida- 

 tion of 1 kg of its wet material. Using these data, V. Jashnov has calculated 

 that the amount of food needed for Calanus finmarchicus in the Barents Sea 

 must be 290 to 480 tons under every 1 km 2 of the sea surface ; and since 

 Calanus finmarchicus feeds mainly on phytoplankton, it is possible to estimate 

 the minimum value of the production of phytoplankton in the Barents Sea, 

 although its true value must be considerably higher. Let us remember that the 

 estimation of the annual production of phytoplankton by the consumption of 

 phosphates, carried out by Kreps and Verzhbinskaya, gave a quantity of the 

 order of 3,000 to 5,000 tons of wet weight under every 1 km 2 of the sea surface, 

 and that even this figure, as we have said, must be recognized as considerably 

 lower than the actual one. 



On the other hand, since Calanus finmarchicus is a one-year animal, we can 

 assume that the PjB ratio for the Barents Sea is about 1 . 



Nutritional value of plankton. As in other seas of the world ocean, Calanus 

 finmarchicus of the Barents Sea is, as a mass form of Copepoda, one of the 

 main links in the food chain of the pelagic region. Huge masses of herrings, 

 haddock and the fry of various fish are fed on this crustacean medusa and 

 ctenophores, which devour enormous numbers of Calanus finmarchicus and 

 are great rivals of theirs. 

 As stated above, Calanus finmarchicus breeds once a year in the Barents 



Table 36. Average chemical composition of Barents Sea plankton in millions of tons 



after V. Jashnov. 



Wet weight 

 Dry weight 

 Protein 



38-6 

 6-4 

 3-9 



Fat 



Chitin 



Ash 



11 

 0-2 

 1-2 



