DISTRIBUTION AND MIGRATION 



339 



Figure 185. Coastal migration of Blue Whales {black lines) and Fin Whales [dotted lines) 

 in the northern hemisphere. Little is known about their migrations across the open seas. In 

 these waters, the migrations of Humpback and Biscay an Right Whales largely correspond with 

 that of Blue Whales, but in the Pacific they correspond with that of Fin Whales. 



respectively. These findings were confirmed by Japanese biologists. 

 Jonsgard also found that during the summer of 1952, the oil yield expressed 

 in barrels per B.W.U. was: Norway, 61-66; British Columbia, 71; and 

 Kamchatka, 64; as against the Antarctic average of about 120. The 

 hypothesis that all these differences are due to the food situation is borne 

 out by observations that Blue, Sei and Sperm Whales in the N. Pacific 

 are all correspondingly smaller at sexual maturity than their southern 

 counterparts. 



Northern and southern Rorquals differ not only in physical develop- 

 ment but probably in migratory habits as well, since the northern groups 



