454 DISCOVERY REPORTS 



numbers, but it is still uncertain to what extent the krill attracts large communities of 

 whales round the less known fringes of the Antarctic Continent. The data upon which 

 the present paper is based are, of course, restricted to the whales caught at South Georgia 

 and Saldanha Bay, but it is convenient at this point to refer to the connection which 

 exists between South Georgia and other parts of the Antarctic and sub-Antarctic. 



Our knowledge of the whole stock of whales, so far as it is derived from the examina- 

 tion of whales at a whaling station, depends largely on the fact that there is very little 

 discrimination in the killing of the whales in any particular area and that the nature and 

 composition of the catches are therefore likely to be fairly representative of the nature 

 and composition of the whale population of that area. Then, if that area is frequented 

 by large numbers of whales of all ages and conditions, one can at least derive from it 

 some idea of the probable nature of the whole stock. The danger of assuming too freely 

 that the whales killed form a representative sample of the whole stock has already been 

 pointed out (p. 430), and before a really thorough knowledge of the whole stock can be 

 gained, it is desirable that observations should extend to a number of different localities 

 so that comparisons can be made between the different whale populations, and the 

 whole stock viewed from more than one angle. 



In this connection a comparison between the catches at South Georgia and South 

 Africa is of considerable interest, for it shows a striking contrast and serves to illustrate 

 the segregation of different classes of whales and their distribution in different localities. 



At Saldanha Bay Fin and Blue whales of two kinds are to be distinguished. There 

 are (i) small immature whales which are relatively abundant, and (2) large and fully 

 mature whales which are relatively scarce^. The former actually constitute 80 to 90 per 

 cent of the whole catch. The length-frequency curves (Figs. 152, 153, pp. 440 and 441) 

 show that intermediate-sized whales are very rarely taken. This being so, the large and 

 small whales must be regarded as quite distinct. It is probable that the small whales are 

 for the time being staying in this locality, feeding on what krill they can find, or are at least 

 not actively migrating, while the large whales are taken while travelling past that part 

 of the coast. This suggestion is supported by the greater regularity in the appearance 

 of the smaller whales and the much better condition of the large whales, which, as has 

 already been pointed out, have comparatively thick blubber although they have little 

 or no food in their stomachs. There appears to be very little change in the composition 

 of the local whale population during the season. 



At South Georgia the constitution of the whale population is entirely different, and 

 is much too complex to be classified into two simple groups. It is more representative 

 than in the vicinity of Saldanha Bay, but there are considerable fluctuations in the 

 numbers of whales, and indications of influxes and eflluxes of different classes of whales 

 during the season. The size and nature of the catches also varies, sometimes to a great 

 extent, from season to season. The most obvious points, however, in which the whales 

 of South Georgia differ from those of South Africa are their greater abundance and 

 the fact that the majority are adult. 



1 This is commented on by Risting, 1928, p. 37. 



