U-378 continued to operate in northern waters such as the Barents, Greenland and Norwegian seas until April 1943 when her sphere of operations changed to the Atlantic Ocean.
The water was warm in the western Atlantic but cold in the Norwegian sea, he said, and "we don't know where the ice was when it started to grow."
For example, in Norwegian sea, one intermediate layer of salinity slightly less than 34.9 was found below the water mass with temperature and salinity maximum.
Especially important are the North and Norwegian seas.
When Safari had sailed, Coombes knew that Nato's surface forces were unobtrusively streaming for the Greenland and Norwegian seas.
Unions plan to shut the Heimdal, Norne and Grane fields, in the North and Norwegian seas, on Sunday night, bringing the total to 720,000 barrels, they said Wednesday.
Carrier Battle group 14, sailing in the north Atlantic, is the closest American Naval asset and is ordered into the Norwegian sea to intervene.
The fishing grounds of the Barents, White and Norwegian seas lie hundreds of miles away.
While this year's North Sea quota was cut, the hunters have been encouraged to intensify their activity further north in the Barents and Norwegian seas.
Dahl suggests that the mix-up was in part due to Quisling's earlier statement to the Germans that he "did not believe" the Norwegian sea defences would open fire without previous orders to do so.