THE STOCK OF WHALES 293 



THE REDUCTION OF WHALING DURING THE WAR 



Discussions in this paper on the condition of the stock of whales arise from circum- 

 stances which existed before the outbreak of war. Since then whaling has been much 

 reduced, and the effect of the industry on the stock is a matter of little application at the 

 present time. However, it is to be supposed that questions relating to the stock will 

 assume importance after the war, and it has seemed desirable that the relevant data 

 should in the meanwhile be examined as fully as possible. 



The reduced activity of the fishing industry in European waters during 19 14-18 re- 

 sulted in a notable recovery in the stocks of fish. Since the reproductive capacity of 

 whales cannot be compared with that of fish, it does not of course follow that the present 

 respite will have a parallel effect, though it must be beneficial. If whaling is resumed on 

 any large scale it would be of much importance to obtain without delay any data which 

 would allow a comparison of the condition of the stock before and after the war. 

 Average lengths and the percentage of immature whales in the catches should be in- 

 structive in this connexion, but possibly more valuable would be observations on ovaries, 

 for any recovery in the stock should be reflected in an increase in the average number of 

 corpora lutea in samples properly comparable with pre-war data. A measurement of 

 the result on the stock of the reduction or cessation of whaling for a number of years 

 would not only be of value per se but might also throw new light on the actual rate of 

 regeneration of the stock. 



SUMMARY 



The preceding paper is based on the more direct observations on whales carried out 

 by the Discovery Committee, and the results are correlated with statistics of the whaling 

 industry. The work is incomplete in so far as a large body of data on the ovaries of 

 whales has not yet been fully analysed. 



1 . No evidence is found to suggest that the well-known species of whalebone whales 

 in the Southern Ocean can be divided into any subspecies or races such as might imply 

 separate stocks of whales, but there appear to be distinct colour varieties of Humpbacks. 

 The small Blue whale known as Myrbjonn and the small dark Fin whale distinguished 

 by the whalers are sexually immature, but may also represent colour varieties of those 



species. 



2. Mean lengths at birth are estimated to be approximately as follows : 



Blue 7-0 m. (23-0 ft.) 



Fin 6-5 m. (21-3 ft.) 



Humpback 4 , 5-5 -0 m - (i4-8-i6-4 ft.) 



Sei 4'5 m - (H' 8 ft -) 



Southern Right 6-o m. (197 ft.) 



A larger number of records of the largest foetuses and the smallest calves may yet call 

 for some adjustment of these figures, but it is believed that they are not far from correct. 



nvYii J 



