THE BLACK SEA 



459 



of bullheads (among them Mesogobius batrachocephalus, M. gymnotrachelus, 

 Neogobius rata, N. platyrostris, N. syrman). Krotov (1949) traces a connection 

 with later immigrants from the Caspian Sea : the Acipenseridae (Huso huso, 

 Acipenser guldenstradti, A. stellatus, A. nudiventris and A. ruthenus), Clupeidae 

 (Caspialosa kessleri pontica, С brashnikovi maeotica, С caspia nordmanni, 

 С. с. tanaica, С. с. paleostomi), salmon (Salmo trutta labrax), Benthophilus 

 Benthophilus macrocephali magistri and B. stellatus), Benthophiloides brauneri, 



Fig. 221. Diagram of estuary of river Danube (Carausu, 1943). Localities where 

 biological samples were taken. 



Caspiosoma caspium, some species of bullheads (Neogobius melanostomus, 

 N. cephalarges, N. kessleri, N. fluviatilis and Proterorhinus marmoratus) and 

 the stickleback Pungitius platygaster ; no fewer than 39 species in all. Most of 

 the Black and Azov Sea fish are immigrants from the Mediterranean after the 

 Dardanelles break-in. They comprise 60 per cent of the whole Black Sea and 

 Azov Sea ichthyofauna, including the fresh-water fish. 



In the Black and Azov Seas the process of species evolution also involved 

 a number of fish of Mediterranean origin such as anchovy, with its Black Sea 

 and Sea of Azov sub-species, the brill, garfish, red mullet and others. A 

 number of fish which enter the Black Sea from the Mediterranean may also 

 breed there (mackerel, Sarda). It has been proved by Wodjanitzky (1940) that 



