MIGRATIONS AND DISTRIBUTION 249 



BLUE AND FIN WHALES 



The migrations of Blue and Fin whales are not so clearly defined as those of Hump- 

 backs. They do not frequent coastal waters in the winter in the same way as Humpbacks, 

 and direct observation is therefore more difficult. Furthermore, although whale marking 

 has provided much valuable information on these two species, it has not yet demon- 

 strated the range and direction of their annual migrations as it has for Humpbacks. All 

 marking has been done in the Antarctic, for Blue and Fin whales cannot be found in 

 sufficient concentrations in warmer waters in winter, and although many marks have 

 been recovered in the Antarctic, only one from a Fin whale, and none from any Blue 

 whale, has so far been recovered in warmer regions. This is not at all surprising, for the 

 majority of Blue and Fin whales taken in warmer waters are small and immature, and 

 cannot constitute a fair sample of those which have been marked in the Antarctic. Even 

 if, in their northward migrations, the Blue and Fin whales cover distances comparable 

 to the distances covered by Humpbacks, it is evident that the majority of at least the 

 adult population do not resort to the coastal waters of the southern continents or come 

 within range of the land stations and factory ships which operate in winter in temperate 

 and tropical regions. 



The single instance mentioned above of a marked Fin whale being taken in these 

 waters is referred to by Rayner (1940, p. 268 and pi. lix). The mark was recovered at 

 Saldanha Bay, Cape Province, from one of the comparatively few adult Fin whales which 

 approach the South African coast. The whale was marked z\ years earlier in the Ant- 

 arctic almost directly south of the Cape of Good Hope. This appears to be the only item 

 of direct evidence of a long-range northward migration of Fin whales. The indirect 

 evidence for supposing that both Blue and Fin whales regularly undertake such migra- 

 tions may be summarized as follows. 



In the first place, Blue and Fin whales are closely related to Humpbacks, and since 

 their habits, especially in relation to feeding and breeding, are very similar, one would 

 expect them to undertake migrations of some similar nature. This expectation is sup- 

 ported by the statistics of catches in different localities, by changes in the composition 

 of the catches during the Antarctic whaling season, by variations in the fatness of the 

 whales, and by the incidence of parasites and scars. 



Perhaps the best evidence for a migration to the Antarctic in summer and to temperate 

 regions in winter is the fact that the whalers have seldom found it worth while to operate 

 in the Antarctic in winter or in the warmer waters in summer. Various authors have 

 commented on this (e.g. Harmer, 1931, p. 108, etc.). At South Georgia the whaling 

 season has usually lasted from September or October to April or May, and in the 

 Antarctic pelagic whaling, before a restricted season was imposed by international agree- 

 ment, the season covered much the same period, the largest catches being in December, 

 January and February. On the other hand, at such centres as Saldanha Bay and Durban, 

 the two principal stations at which Blue and Fin whales are taken in warmer waters, the 

 season lasts from April or May to October or November. This is most readily explained 



