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4. Pollack {Gndus polhi chilis L.) 



Only the northern boundary lies within the regions investigated. On account of its 

 requirements for high tempeiatures and moderate depths the pollack is excluded from 

 spawning over large parts of the regions. 



It is quite lacking at Iceland and at the Fseroes reproduces very little. On the other 

 hand it spawns on the British Atlantic coasts, in increasing quantities from north to 

 south. Within the regions investigated it spawns in greatest quantities in the Channel. 

 It spawns in the North Sea and Skager Eak but in smaller quantities and later in the 

 year than on the Atlantic coasts and in the Channel. (There is no spawning in the 

 Kattegat nor in the Baltic.) 



The boundaries for the spawning are: 



northern limit; the Fseroes (including these); 



southern limit: south of the regions investigated; 



minimum temperature: a little less than 8°; 



maximum temperature: ? 



principal spawning time: spring and early summer. 



5. Haddock {Gadus œglefinus L.) 



Both the northern and southern boundaries lie within the regions investigated. In its 

 requirements as to depth, salinity and temperature the haddock has an intermediate posi- 

 tion between the cod and the coalfish, being more particular than the former' and less 

 than the latter^. It spawns but little in less than 50 or more than 200 meters depth. 

 The production of the fry occurs in greatest quantity at S. and S. W. Iceland, the Faroes, 

 on the British Atlantic coasts and in the northern part of the North Sea. On the other 

 hand the haddock spawns but little or not at all at N. and E. Iceland , in the Bay of 

 Biscay, the English Channel and the southernmost part of the North Sea. 

 The boundaries for the spawning are: 



northern limit: the warmer parts of the Icelandic waters (including these); 



southern limit: the waters S. of Ireland (including these); 



minimum temperature: ca.5'/2°^6°; 



maximum temperature: ca. 9° — 10°; 



principal spawning time: spring. 



6. Whiting (Gadus metiangus L.) 



Both the northern and southern boundaries lie within the regions investigated. The 

 whiting belongs to the species which are able to reproduce in very shallow depths and 

 low salinities, as appears at once from the fact that spawning takes place in the Kattegat 

 and the southernmost part of the North Sea. In this regard it resembles the cod, but in 

 agreement with its greater distribution southward it requires higher temperatures than the 



^ Thus in contrast to the cod the haddock does not ppawn in the southern part of the JSattegat, 

 nor in the Belt Sea or Baltic , where the salhiity of about 35 "/oo seems to be the minimum for the 

 spawning of the haddock. 



'' lu contrast to the coalfish the haddock spawns in the Skager Kak, where tlie salinity is too low 

 for the spawning of the coalfish. . 



