2S 8 DISCOVERY REPORTS 



siderable numbers of whales were seen from time to time, but on each occasion whales 

 were scarce between no and 130 W. No whaling has been done in this part of the 

 Antarctic, and it is not covered by Hjort, Lie and Ruud's areas I-V. Their area I was 

 a small area arbitrarily arranged for the now obsolete whaling around the South Shetland 

 Islands. It would seem reasonable now to call the south-eastern part of the Pacific 

 sector area I, and this would accommodate the 'Chilean' group of Humpbacks (see 

 Table 14, p. 246) and the peak of ' observed ' whales seen in Fig. 7 between 90 and 

 ioo° W. The western boundary of area I can be provisionally fixed at 120 W, and since 

 Hjort, Lie and Ruud fixed 170 W as the eastern limit of area V, the sector between 120 

 and 170 W can be called area VI pending fuller information on the distribution of 

 whales on this side of the Antarctic. These areas I-VI are shown in Fig. 8. We should 

 not expect to find Humpbacks in area VI for, as mentioned on p. 246, the coastal regions 

 on the east and west sides of the Pacific have been connected with the Humpback groups 

 in areas I and V. It may be, of course, that there is no real boundary between areas V 

 and VI, for although Fig. 7 shows a gap at this point it is clear from Fig. 8 that the 

 observations of the 'Discovery II' did not fairly sample the region around the 180th 

 meridian. 



It seems that we are at least justified in concluding that Blue whales, and possibly also 

 Fin whales, in the Antarctic summer tend to segregate in the same five regions as the 

 Humpbacks, but that, while in Humpbacks the segregation is almost complete, in Blue 

 whales the tendency is apparent only in the fact that rather larger numbers are to be 

 found in the areas of concentration than elsewhere. The numbers of ' Fin whales per 

 day' in Figs. 5 and 6 do not show any clear segregation of this species in areas II-IV, 

 but it is believed that the ' observed ' whales in Fig. 7 include far more Fin whales than 

 other species, and here there are distinct signs of segregation. Whale marking also (see 

 below) suggests that Fin whales in the different areas may belong to distinct com- 

 munities. The evidence for the segregation at least of Blue whales is based (a) on the 

 division of the whaling fleet into separate groups which presumably represent the 

 opinion of experienced whalers as to the localities in which whaling is most successful, 

 (b) on comparisons of the catches in different longitudes which are treated as samples 

 of the density of the whale population, and (c) on the whales marked or shot at by the 

 'William Scoresby' which are treated in the same way. Figs. 3, 5 and 6 are perhaps 

 liable to misinterpretation in their details, for the statistics are to some extent influenced 

 by extraneous factors, but this hardly affects the general conclusion. Some support is 

 to be found in the observations of the ' Discovery II ', and these observations suggest 

 provisional boundaries to the new areas I and VI in the Pacific sector. 



The recoveries of whale marks described by Rayner (1940) are of special importance 

 when considered in relation to the grouping of Blue and Fin whales. His charts showing 

 the positions of marking and capture of Blue and Fin whales killed in the same season 

 as they were marked (pi. xlvii and liv) clearly show separate groups of whales in areas 

 II-IV, none of which has moved from one area to another. As he points out, however, 

 there is some lateral dispersal after an interval of a year or more. Thus after one or two 



