THE STOCK OF WHALES 281 



for each area. This species, as we have seen, is, and possibly always has been, more 

 abundant than the Blue whale, but it has been caught in increasingly large numbers 

 owing to the scarcity of Blue whales, and it is not to be supposed that it could long 

 withstand the pre-war intensity of whaling without showing signs of depletion, especi- 

 ally as it is necessary to take two Fin whales to equal the yield from one Blue whale. 



It is certain that the stocks of Humpbacks have suffered severely from hunting. This 

 species is more easily approached than other species, and its habit of concentrating in 

 certain regions, especially off the continental coasts in winter, make it more than ever 

 vulnerable. The effects of hunting do not perhaps become manifest in quite the same 

 way as, for example, in Blue whales. It has been shown above that the Humpbacks are 

 divided into much more clearly separated communities than Blue whales, and hence, 

 rather than a general decline in numbers, we should expect heavy local depletion in 

 regions where Humpbacks are taken in large numbers, while the species may still be 

 abundant enough in other localities. Thus, as is well known, the Humpbacks were 

 heavily depleted in the South Georgia region in the early years of the southern whaling 

 industry, while they were subsequently found to be still abundant in areas III and IV 

 when the activities of factory ships spread to the Indian Ocean sector of the Antarctic. 



The destruction of the stocks of Humpbacks has been described among others by 

 Matthews (1937, p. 82), who points out that, wherever new whaling grounds have been 

 opened up, the Humpback has always been the predominant species in the first few 

 years, and then rapidly declined in numbers. This certainly applies to the industries at 

 South Georgia, Natal, the Congo, and Angola (see Table 10, p. 234), though some of 

 these places have shown a partial recovery. Off Western Australia the stocks appear to 

 have survived the fishing in 19 12-15 and 1925-8, but it could not be expected that the 

 populations here and off Madagascar could have maintained their numbers for long 

 against the slaughter that was going on in 1936, 1937 and 1938, especially as the same 

 stocks were being attacked in areas III and IV in summer in the Antarctic. 



However, at the International Conference of 1938 it was agreed to prohibit the 

 catching of Humpbacks by factory ships in the Antarctic for a year in the first place ; 

 and the reduced intensity of whaling in war time will also relieve the situation. 



RELATIVE DEPLETION OF DIFFERENT SPECIES 

 It was tentatively estimated above (p. 266) that the ratio of the stocks of Blue, Fin 

 and Humpback whales in the Southern Ocean is of the order of 15, 75 and 10 % 

 respectively. The Humpback ratio is the most doubtful of the three, but it is certain 

 that there are far more Fins than either Blues or Humpbacks, and it is probable that 

 Humpbacks are slightly scarcer than Blues. For this reason alone we might expect that 

 if whales need protection at all these two latter species need it. It has been shown that 

 they have in fact suffered substantial depletion, and there is every reason to suppose 

 that this depletion would be progressive (so long as the catching capacity of the industry 

 was maintained) until a point was reached at which it was no longer worth while to hunt 

 them. This point has not yet been reached except in case of Humpbacks in certain 



