324 WHALES 



Australian Area) ; Area V: 130° E.-i 70° W. (the E. Australian Area) ; and 

 Area VI: 170° W.-i20° W. (the W. Pacific Area, a recent sub-division of 

 the former Area I, i.e. 1 70° W.-6o° W.). In the accompanying figures, the 

 old division is still observed. The distribution of whales in these areas is 

 far from uniform. We have seen that Humpbacks keep to certain regions, 

 and Sperm Whales, while found in all areas, are caught chiefly at 25° W., 

 3O°-50° W., and I20°-I30°E. Starting from Area II, the percentage of 

 captured Blue Whales increases as we move farther east, while that of 

 Fin Whales decreases. Thus, from 1947 to 1954, the percentage of captured 

 Blue Whales was 25 in Area II, 33 in Area III, 36 in Area IV, and 41 in 

 Area V. These figures are corroborated by observations made aboard the 

 Discovery II, and it would appear that the differences between the various 

 areas are due more to natural factors than to man's intervention. Possibly 

 the explanation must be sought in ice-conditions, since it is a known fact 

 that most Blue Whales keep to drifting ice while the majority of Fin 

 Whales is found just outside it. Prof. Ruud has estimated that, in the ice. 

 Blue Whales represent 50 per cent, and outside the ice only 10 per cent 

 of the total Blue and Fin Whale population. The causes of this pheno- 

 menon are not known. 



The statistics also show clearly that the oil yield decreases as we move 

 east from Area II. Now, the oil yield of whales is expressed in barrels per 

 Blue Whale Unit, a barrel being one-sixth of a ton, and a B.W.U. being 

 one Blue Whale, or two Fin Whales, or 2 -5 Humpback Whales, or six Sei 

 Whales, all irrespective of length. If we look at the figures for the years 

 after the Second World War, we find an average yield of 1 35 barrels per 

 B.W.U. in Aiea II and also in the eastern part of Area I, of 121 barrels 

 in Area III, of 1 17 barrels in Area IV and of 1 16 barrels in Area V. As 

 Area I has only been reopened to whalers since the 1955-6 season, the 

 figures for the Pacific part of Area I will not be dealt with here. 



The statistical results, in themselves, do not entitle us to assert that 

 whales get fatter towards the Western areas, since they represent weekly 

 totals of oil gained from all whales except Sperm Whales. Now, it is not 

 absolutely certain that Blue Whales are always twice as fat as Fin Whales, 

 as the definition of the B.W.U. might have misled one into thinking.^ 

 Thus if two Fin Whales were to yield more oil than one Blue Whale, the 

 decrease in the number of barrels per B.W.U. from west to east may well 

 be due to the known fact that the percentage of Blue Whales increases in 



' In the absence of adequate data, various experts believe that, at least in the second 

 half of the season, Blue Whales do in fact yield roughly twice as much oil as Fin Whales. 

 When the results of Jonsgard's recent investigation into the oil yields of individual 

 Rorquals are completed, we may know more about this subject, even though he worked 

 with specimens caught by Norwegian land stations, which may not be representative of 

 Antarctic Rorquals. 



