THE BARENTS SEA 



177 



meet the local cold ones goes through continuous and fairly substantial 

 changes, with warm-water forms now advancing, now receding, and being 

 replaced by the cold-water ones. These migrations depend directly on the 

 climatic changes, primarily on the greater or smaller thrust of the warm 

 Atlantic waters. 



History of fauna development. As yet the palaeogeographical changes of the 

 Barents Sea during the Tertiary and Quaternary periods have not been 

 sufficiently investigated. As has been said above, a rise in temperature of the 



Fig. 75. Penetration of boreal forms into Barents Sea. 1 Littoral fauna; 2 

 Fauna of upper horizon of sublittoral ; 3 Boreal pelagic fauna (Derjugin's 

 boundary) ; 4 Boundary of boreal and Arctic faunas (Filatova) ; 5 Direction 

 of migration. Places where cold-loving bottom-living fish Ly codes agnostus 

 (6) and Lycodes vahli v. septentrionalis (8) and the thermophilic Lycodes 

 seminudus (7) (Knipovitch) are found. 



M 



