GENERAL CHARACTERISTICS OF THE EASTERN SEAS 741 



Table 300. Pacific and Atlantic cod, annual gain in weight, kg (P. Moiseev, 1953) 



differences, vary greatly in their ecology and mass development. Many mass 

 forms found developed in one basin occupy a secondary place in the other. 

 The cod is subject to long distance seasonal migrations in the North Atlantic, 

 but in the Pacific its movements are limited to local seasonal vertical trans- 

 positions which are characteristic also of certain other fish and of commercial 

 crabs (Fig. 364). 



However, the new data from the results of tagging cod at different points 

 of the eastern coast (I. Polutov, 1952) have shown that cod may migrate from 

 the Avachinsky Bay not only into the Kronotsky Bay, but much farther north 

 to the Olyutor Inlet thousands of kilometres away. However, even such 

 journeys cannot be compared with the long migrations of cod in the Atlantic. 



Among the distinguishing features of the seas of the northwestern Pacific 

 as compared with those of the eastern Atlantic P. Moiseev (1953) notes the 

 higher velocities of its currents, leading to the formation of a series of 

 biological peculiarities in the fish. Thus the Pacific cod has the ova of a 



Fig. 364. Diagram of cod migrations within the area of Karagin Island and Olyutor 

 Inlet (Moiseev, 1953). 1 Shoaling of cod; 2 Months of shoaling; 3 Spawning region. 



