496 



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



9. SYNDESMYA OVATA 

 10. POLYCHAETA NEPHTHYS HOMBERGl" 



II. MOLUSC HYDROBIA VENTROSA 



1. PONTOGAMMARUS MOEOTICUS 



2. BEDS OF ZOSTERA MARINA 



3. MYTILASTER LINEATUS 



4. NEREIS SUCCINEA 



5. A STONE WITH BALANUS IMPROVISUS 12. BRACHINOTUS LUKASI 



6. CARDIUM EDULE 13. OSTROUMOVIA 



7. NEREIS DIVERSICOLOR M. BLACKFORDIA 



15. GOLDEN SHINER 



8. CARBULOMYA MAEOTICA 



16. PIKE PERCH 



17. ANCHOVY 



18. CLUPEONELLA 



19. STURGEON 



20. STARRED STURGEON 



Fig. 237. Character of the distribution of the main forms of the Sea of Azov fauna 



(Zenkevitch). 



considerably richer Black Sea fauna, which in its turn is a selected fauna 

 from the Mediterranean. In spite of this, a certain number of Mediterranean 

 forms find in the Sea of Azov conditions exceptionally favourable for their 

 development and form huge accumulations. As a result, the communities of 

 the Sea of Azov are often characterized by their large biomass and by their 

 high productivity indices and, at the same time, by the extreme poverty of 

 their qualitative composition (oligo-mixed communities). Of the 137 species 

 of benthos only 30 species are found more or less frequently. 



