i8o 



DISCOVERY REPORTS 



made on the South Georgia grounds (5713) was in season 1925-6, and the greatest catch 

 of Blue whales (3670) in 1926-7. Both these maxima fall in the first of our four-year 

 periods. The average number of catchers is approximately the same in each period; but 

 in the second much more time was occupied in towing whales long distances to the 

 shore stations and in consequence less time was spent in hunting. 



Table IX 



The results cannot be interpreted as giving more than a strong suggestion that there 

 has been a large reduction in the stock, and the indication is that Blue whales have 

 suffered more heavily than Fin. It is perhaps significant that the great development of 

 pelagic whaling along the Weddell Sea ice-edge falls within the second four-year period 

 and that in this area the incidence of capture falls more heavily on Blue whales. 



The figures in the last column of Table IX give only the average density of whales 

 killed on the South Georgia grounds. It will be evident that they were taken in much 

 greater numbers in the centres of concentration and in much smaller numbers on the 

 fringe of the whaling grounds. The greatest concentration during the eight seasons was 

 of Fin whales in 1925-6. In April alone of this season 92 Fin whales per 100 square 

 miles were killed a short distance from the mouth of Cumberland Bay, and in the same 

 area the catches for the whole season amount to 2-8 Fin whales per square mile of 



whaling ground. 



Inspection of the charts for the different seasons gives the impression that the whales 

 generally pass across the grounds in an easterly direction. The first whales of the season 

 are usually taken to the north or north-west of the island. As they increase in number 

 their centres of concentration shift to the east and later, in most seasons, they move 

 towards the southern side of the island. At the end of the season there is considerable 

 variation in position, but the tendency is for whales to occur in the south-east. In some 

 of the charts (Fin whales, 1928-9, Plate XII, afltords the best example) the disappearance 

 of a school in the early part of the season and its replacement by later arrivals can be 

 traced. 



