2 68 DISCOVERY REPORTS 



miles away. The importance of this third recovery is to be found in considering its 

 relationships with two whales (Nos. 4091, 10515/17) killed as members of the i-Group. 

 One of these (No. 4091) was marked near South Georgia some 2342 miles, almost 8o° of 

 longitude, distant from the position of marking of No. 5834; these two whales were 

 killed on positions only 251 miles, actually less than 6° of longitude, apart. The third was 

 marked in the same region where the other two were killed, but was captured in the 

 mouth of the Weddell Sea. These recoveries may be considered to establish the inter- 

 mingling of Fin whales over the wide area from Enderby Land to the Bellingshausen Sea. 

 This intermingling is further illustrated by two whales (Nos. 2770/1, 2807) marked, 

 again on the same day and position, off Enderby Land and captured far to the east on 

 the grounds off Queen Mary Land. The distances between marking and recovery of 

 these two are more than 1 100 miles and more than 500 miles respectively. Thus, of five 

 whales marked in a small area off Enderby Land and captured after two years, two show 

 a divergence of 2223 miles and of 89 of longitude. 



The 1 -Group and the 2-Group recoveries provide connecting links between the 

 Bellingshausen Sea and the whaling grounds off Queen Mary Land, over almost half 

 the Antarctic periphery. These returned marks indicate the homogeneous character of 

 the Antarctic Fin whale population over the whole region covered by the whaling 



fleets. 



One Fin whale (No. 3482) marked in Antarctic waters has been taken in warmer 

 regions to the north (Plate LIX). This whale was marked in February 1935 on 65 S; 

 it was then noted to be a calf accompanying its mother. It was captured off Saldanha 

 Bay, South Africa, on 1 July 1937, 1900 miles distant and almost due north of the 

 position on which it was marked. The data returned with the mark gave this whale as a 

 female 68 ft. 9 in. (20-97 m -) in length. No estimate was made of its length when marked, 

 but it was then small enough to be confidently recorded as a calf accompanying a cow. 

 This implies that its length then could not have been more than 40-45 ft., perhaps less, 

 but not much less, for if it had been much under this length a note suggesting small size 

 would certainly have been made. Accepting this estimate of the whale's length when 

 marked, a length corresponding closely with that of 12 m. given by Mackintosh and 

 Wheeler (1929) as the probable length of weaning in Fin whales, the whale shows a 

 linear increase over the period of 862 days of 75 per cent. It may be confidently assumed 

 that at the time of marking this whale was already several months old, and if this were 

 so, the age of the whale when killed must have been about three years. Its length 

 (20-97 m.) is a little more than that (20 m.) considered by Mackintosh and Wheeler 

 (foe. cit.) to show the attainment of sexual maturity, which they suggest is normally 

 reached after about two years. But this small excess is not inconsistent with an age of 

 fully three years, for growth after the attainment of sexual maturity can be very slow 

 and may even cease at a length not much exceeding the mean length at sexual maturity. 

 On the other hand, if this whale had been new born at the time of marking its develop- 

 ment would have corresponded very closely to the growth curve for female Fin whales 

 given by Mackintosh and Wheeler (foe. cit.). 



