HYDROLOGY OF THE BRANSFIELD STRAIT 59 



by no means certain that the same differences in temperature and salinity noted would 

 be repeated every November and February, although it may seem probable that the 

 current from the Weddell Sea is stronger and reaches farther westward in February 

 than in November. Our material does not allow of a more detailed discussion of seasonal 

 variations. 



NOTE ON THE PRESENCE OF ICE IN THE BRANSFIELD 



STRAIT AND ON THE CURRENTS THROUGH THE STRAITS 



SEPARATING THE SOUTH SHETLAND ISLANDS 



The operation of scientific vessels and the whaling fleet inside the Bransfield Strait 

 has been limited to the short season November to April, and as far as our knowledge 

 goes no ships have been present in this area in the southern winter. Much ice prevails 

 in the strait in early spring and late summer and it is not known whether the strait is 

 entirely closed to navigation in winter. According to a private communication from 

 Mr Nielsen of the Hector Whaling Company, who has spent many whaling seasons at 

 Deception Island, it is his opinion that the strait is never completely closed to navigation. 



The approach of winter conditions in the Bransfield Strait is marked by the appearance 

 of pack-ice at the north-eastern end of the strait ; the ice then spreads across the strait at 

 this end and down the Trinity Peninsula coast. When this accumulation of pack-ice has 

 rendered whaling too difficult the whaling fleet has usually ceased operations for the 

 season and has left the area. On their return in spring the whalers find, in years when 

 not much ice is present, that the Bransfield Strait is either free or easily navigable at the 

 end of October or the commencement of November. When, however, much ice is 

 present the whaling factories have been considerably delayed in their endeavours to 

 reach their anchorages in Deception Island or Admiralty Bay in King George Island, 

 and may only be able to force their way into the strait in late November. 



The position of the pack-ice in the south-western part of the strait in autumn and 

 early spring appears to be regulated chiefly by the direction of the wind. Thus in the 

 whaling season 1920-1 northerly and north-easterly winds prevailed from the end of 

 November 1920 to the beginning of February 1921 and the ice which earlier had been 

 carried north-east in calm and fine weather by the current close to the southern side of 

 the South Shetland Islands was driven back in a south-westerly direction. The ice was 

 still present in the eastern part of the Bransfield Strait in late February. On the other 

 hand in the season 192 1-2 the south-east side of the strait was free on November 25 

 1921 while the whole of the northern side was blocked, these conditions prevailing until 

 January 1 1922, when the ice finally moved out in a south-westerly direction. The ice in 

 the Bransfield Strait normally moves out of the strait to the north-east. In December 

 1923, contrary to usual, ice began to form in the sea east of Trinity Peninsula and 

 Joinville Island towards Cape Melville. In March 1924 ice was moving to the south- 

 west right into the middle of de Gerlache Strait. Had the north-east current not been 

 flowing in the Bransfield Strait the whaling ships would have had to leave Deception 

 Island as at certain times the ice pressed right up against the island. The easterly parts 



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