RELATIVE ABUNDANCE OF SPECIES 265 



are some obvious discrepancies in some areas. However, in areas II and III in which 

 the number of whales observed and the number shot at are both fairly large, the pro- 

 portions are not much different. In area IV the observed whales are so scarce as to be 

 of little value. The whales shot at in area IV include a very high proportion of Hump- 

 backs, but this is not necessarily representative of the real proportion, for if the ' William 

 Scoresby ' met with a sufficient concentration of them a special attempt might be made 

 to mark as many of this species as possible, to the neglect of other species. 



The interpretation of the data is thus subject to a good many qualifications, and with 

 the available material we cannot make any very accurate estimate of the species ratio in 

 the Southern Ocean as a whole, especially in view of the fact that the ratio has almost 

 certainly been changing from year to year. In certain areas, however, an estimate can 

 be made which should be reliable within certain limits. 



In area II the data from whale marking and observation are as follows : 



The quantity of data on which these figures are based can be seen from Tables 18-20. 

 The South Georgia marking data apply to a very limited locality in area II, and are 

 included here only because they seem to support the ' observed ' data rather than the 

 'William Scoresby' data. The latter were acquired in the 1937-8 season, the marking 

 at South Georgia covered the period 1932-7, and the 'observed' whales were logged at 

 various times between 1926 and 1939, though not many of these identifications were 

 made before 1930. There is reason to believe that the stock of Blue whales is being 

 reduced more quickly than the stock of Fin whales (see p. 282), and this may at least in 

 part account for the low percentage of Blues in the ' William Scoresby 's' data which are 

 in respect of a single recent season. It seems almost certain that in the last two or three 

 years before the war the percentage of Blue whales in area II cannot have been less than 

 3 % or more than about 12 %. Humpbacks have a more patchy distribution, but the 

 percentage of this species is clearly very low. In this area then it seems that of the 

 combined population of Blue, Fin and Humpback whales the recent proportions are of 

 the order of 9, 89 and 2 % respectively. 



The whales shot at by the 'William Scoresby' in area II may be compared with the 

 whales taken by whalers in the same area in the same season as follows : 



Humpback 



% 



2-4 



17 



* Figures from Bergersen, Lie and Ruud (1939, p. 38). 



The agreement here is quite good if allowance is made for the fact that the Blue whale 

 is more valuable to the whalers than the Fin whale. 



