WHALE MARKING 2 6 s 



infiltration from one region to the next may appear to be proceeding only very slowly it is 

 doubtless sufficient to give the whole Fin whale population the uniform character it 

 appears to possess. 



Considering now the i -Group Fin whales around South Georgia, two (Nos. 223, 248) 

 taken in 1933-34 provided the first evidence that these whales remained in the same 

 region or returned to the same region year by year (Plate LV). These two whales were 

 marked in the initial experiment of 1932-33 on the same afternoon in the same large body 

 of whales ; they were killed within four days of each other and almost on the same position. 

 This would appear to show that not only do Fin whales return to the same region from 

 season to season, but that they often do so in the same company. A further six Fin whales 

 (Nos. 6256, 6353, 6890, 6900, 6918, 7258), captured off the east coast of South Georgia, 

 are some of the very large number marked within seventy miles of the Shag Rocks 

 during the season 1936-37, none of which was taken that season on the South Georgia 

 grounds. It seems that during the following season (1937-38) many of the whales that 

 in the previous season had proceeded southwards, well to the west of South Georgia, 

 now passed close to the island as though their southerly route had been shifted a little 

 to the eastwards. 



Eleven more of the Fin whales marked within seventy miles of the Shag Rocks during 

 the season 1936-37 have been returned in the i-Group from the factory ships working in 

 the mouth of the Weddell Sea between the South Sandwich and the South Shetland 

 Groups (Plate LVI). They demonstrate a similar movement to that followed by the 

 o-Group whales: from the position of marking in the vicinity of the Shag Rocks they 

 spread in a fan-wise manner with the predominant direction south. If, however, this 

 stream of movement is considered to have shifted to the east and to have flowed during 

 the season past South Georgia rather than the Shag Rocks the predominant direction of 

 movement would then be west of south. This direction would agree with the general 

 direction of movement of those Fin whales marked by the ' William Scoresby ' early in 

 January 1938 in the southern part of the Scotia Sea and taken the same season (o-Group). 

 Thus it seems probable that many of the whales marked then may have belonged to the 

 same migratory stream as those marked the previous season around the Shag Rocks. 

 That Fin whales were more abundant around South Georgia during the season 1937-38 

 than the previous season is shown by the catches made ; this is especially so for January. 

 There are thus considerable grounds for believing that the large stream of Fin whales 

 which passed the Shag Rocks in the season of 1936-37 was, for some reason, deflected 

 in 1937-38 so as to pass close to South Georgia itself. In such seasonal deflections of 

 streams of migrating whales may be found the explanation of the periodical " Fin whale 

 seasons" which characterize South Georgia whaling. 



It is convenient now to consider the whales marked during the season 1937-38 and 

 returned in the 1 -Group; they are distinguished by having five-figure serial numbers. 

 They are distributed from near Bouvet Island in the east to the Bellingshausen Sea in 

 the west. With the exception of those marked in this westerly region, they do not greatly 

 extend the distribution of the 1 -Group recoveries in this region covering the mouth of 



