664 



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



Bivalves are usually preponderant in the benthos biomass, constituting at 

 times 94 per cent of its total. Chironomids occupy second place, Phryganidae 

 third, and Pontogammams aralensis fourth. Other benthos groups are of little 

 significance. 



All the organisms of Aral benthos are consumed by fish, but only a certain 

 proportion of those of the Azov and Caspian benthos are taken. This fact 



Fig. 314. Distribution of the total benthos biomass (g/m 2 ) 

 of the Aral Sea in 1954-57 (Yablonskaya). 



must be taken into consideration when estimating the food significance of 

 Aral benthos. The significance of benthos as food is thus relatively higher in 

 the Aral Sea. 



Uniform distribution, within the limits of one biotope, and the absence of 

 areas of great concentration, are characteristic of Aral benthos. Even Drei- 

 ssena does not form extensive accumulations here. The phenomenon of 

 bottom-fauna suffocation has not been recorded in the Aral Sea. 



The quantitative and qualitative distribution of the zoobenthos of the Aral 

 Sea has more than once been investigated by V. Nikitinsky (1933), A. Behning 



