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



many fish which need great depths for their development could not become 

 acclimatized in the Black Sea, and for this reason among the Mediterranean 

 communities fish with pelagic ova are predominant in the Black Sea. 



Large numbers of anchovy, mackerel, Sarda, greenfish (Pemnodon saltator), 

 hardtail, tuna, Sprattus phalericus, sardines and others enter the Black Sea 

 in the spring through the Bosporus. Not long ago it was considered that neither 

 mackerel nor Sarda nor tuna multiply in the Black Sea, but only feed there. 

 However, it was shown by V. Wodjanitzky in 1936 that Sarda and tuna 

 multiply in the Black Sea. There are some data too on the multiplication of 

 mackerel in the Black Sea. Besides the large numbers of Mediterranean fish 

 entering the Black Sea, Black Sea fish migrate from the western half of the 

 Sea in large masses to feed in the northwestern part, and from the eastern 

 part into the Sea of Azov through the Kerch Strait. Most favourable fishing 

 conditions are created in the narrow Kerch strait, when a mass of fish 

 (anchovy, herring, Clupeonella, grey mullet, red mullet) are trying to enter 

 the Sea of Azov ; the catch then may amount to 200,000 centners. A large 

 mass of two- or three-year-old anchovy dies during the winter. Fish, mainly 

 the anchovy, which leave the Sea of Azov for the winter and play a very 

 important role in the food of predatory fish and dolphin, move in different 

 years either to the shores of the Crimea or to the Caucasian coast, thus creat- 

 ing a varying picture of the distribution of food resources. Moreover, dying- 

 off in some parts of the Sea (S. Maljatzky, 1934) may form a large accumu- 

 lation of organic substances in its deep layers. 



Fish nutrition. V. Wodjanitzky (1941) has given a diagram of the nutrition 

 relationship among the Black Sea fish (Table 188). 



The main mass of the pelagic Black Sea fish (anchovy, Sprattus, Clupeo- 

 nella, sardines, pelagic pipefish Syngnathus schmidti and the fry of many other 

 fish) feeds on plankton, fattening mostly in the northwestern part of the Sea. 

 Small herring and mackerel feed also mainly on plankton and small fish. 

 Sarda, tuna, greenfish, large herring and dolphins — the real pelagic carnivores 

 — also feed on small fish. One common dolphin (Delphinus delphis), the object 

 of a large fishery industry in the Black Sea, consumes during a year 1-5 to 3 

 million centners offish, i.e. two or three times more than the yield of the Black 

 Sea catch. 



Moreover, Phocaena phocaena is common in the coastal areas of the Black 

 Sea and in the Sea of Azov. The third dolphin species in the Black Sea, Mona- 

 chus monachus, is the fourth mammal form of the Sea. 



According to V. Moskvin's data (1940) the herrings of the northeastern 

 part of the Black Sea differ greatly in their feeding habits, whereas Caspialosa 

 pontica and C. maeotica are typical predators feeding mainly on small fish 

 (chiefly anchovy) and large crustaceans. C. tanaica feeds on lower crustaceans 

 (mainly Calanus helgolandicus) and sea-weeds (Table 189). 



According to A. Makarov's data (1939) mackerel — also a typical pelagic 

 carnivore — feeds mainly on Sprattus, anchovy, smelt and copepods. The diet 

 of hardtail is very similar to that of mackerel ; however, since it is a bottom- 

 living fish, it feeds not on copepods but on mobile benthos organisms, mostly 



