Pavlov, D. S., A. M. Pakhorukov, G. N. Kuragina, V. K. Nezdoliy, N. P. 
Nekrasova, D. A. Brodskiy and A. L. Ersler (1977).  Some features of the 
downstream migrations of juvenile fishes in the Volga and Kuban Rivers. Journal 
of Ichthyology.  17:363-374.
	
The pattern of downstream migration of juveniles of various fish species in the 
Volga and Kuban rivers was studied. With the exception of clupeids 6-10 mm long, 
a daily migratory rhythm was found in all the fish species investigated. The 
migration is associated with the loss of visual orientation by the fish and is 
observed only during the hours of darkness. The downstream migration continues 
round the clock in the Kuban River owing to the low transparency of the water. A 
dynamic pattern has been established in the vertical distribution of downstream 
migrating cyprinid, clupeid and gobiid juveniles throughout the 24 hours. Some 
features of the horizontal distribution of juveniles are noted. The distribution 
of juvenile fishes in the river is regarded as an active process controlled by 
definite behavioral reactions.