THE BLACK SEA 



463 



(which corresponds to approximately 2-0 kg offish per hectare calculated for 

 the whole Sea surface). 



General characteristics of Black Sea productivity 



Our general idea of Black Sea productive peculiarities depends on the con- 

 ception described above of vertical circulation adopted by us. If the vertical 

 circulation goes down to the depth of the Sea, then the latter is not a bottom- 

 less well, absorbing large quantities of organic substances ; but a great part 

 of them is brought back into the inhabited zone. After his comprehensive 

 examination of the problem V. Wodjanitzky (1954) came to the conclusion 

 that the production processes are not weakened in the Black Sea as compared 

 with those in other seas. To confirm his point of view Wodjanitzky reproduces 

 V. Datzko's table, given here as Table 190. 



* The figure is undoubtedly double what it should be. 



In elucidating Table 190 Wodjanitzky adduces the following considerations : 

 that the quantities of nutrient salts (nitrates and phosphates) in the inhabited 

 layer of the Sea are of the same order as in other seas (the nitrate content is 

 somewhat decreased and there is a certain saturation with phosphates and 

 ammonia) ; the salt ratio in the surface and in the depths is, moreover, the 

 same. 



In its inhabited zone the Black Sea cannot be considered as impoverished 

 either in phyto- or zoo-plankton. In any case according to all these indices 

 it is not poorer but richer than the Caspian Sea. As regards its fisheries, the 

 Black Sea occupies a middle position between the Mediterranean and the 

 Sea of Azov. Wodjanitzky thinks that its resources of pelagic fish (anchovy, 

 sprat, Clupeonella, herring, mackerel, garfish, hardtail, Sarda, Pomatomus 

 saltatrix, tuna and others) are very rich, and that from them the fishing 

 industry can be greatly expanded. 



