and then towards October -November begin migrating toward the depths. 

 The younger age groips also perform analogous migrations, but begin them 

 earlier and proceed toward the shore at shallower depths and in the fall 

 depart not so far as mature individuals. Thus, the majority of young 

 flounders hibernate in depths of 15 to ZO meters. The roe of the Zhelto- 

 peraya flounder is pelagic and the larvae which emerge from it direct them- 

 selves toward the shore, and undergo a metamorphosis in the zone very close to 

 the shore and remain until late fall. The migrations of flounders 



are closely linked with the temperature regime of the sea (Moiseev, 1946), 



111 



Fig. 120. Dactylogyrus iwanowi Bychowsky, schematic representation of 

 the life cycle, somewhat simplified (the period of hibernation of the young 

 Leuciscus brandti in the river is not indicated; and for the sake of con- 

 venience it is understood that the young ones descend into the sea com- 

 pletely). Explanation in text. 



According to our observations the infection of the flounder takes 

 place only in the littoral zone and the reproduction of Pr. strelkowi takes 

 place not during the entire warm period but mainly at the end of July and 

 in August. This reproduction has a mass character. From our diaries 

 it is apparent that in the Bay of Anama at the Island of Shikotan the accretion 

 of the quantity of larvae of Pr. strelkowi on flounders of 13-17.5 centimeters 



115 



