270 



DISCOVERY REPORTS 



THE MONTHLY SPECIES RATIO 



It is well known that comparatively few Fin whales appear in the Antarctic catches in 

 the early part of the summer, and comparatively few Blue whales in the later part. The 

 International Statistics (no. vn, pp. 5-8, and no. xiv, pp. 7-8 and 13-14) give for each 

 month in each of the twelve seasons 1927-39 the catch of each species, both in absolute 

 and percentage figures. In recent years pelagic whaling has been restricted to the period 

 November-March, and at South Georgia from October to April. In earlier years, how- 

 ever, whaling sometimes began in September and lasted into May. For a concise indica- 

 tion of the changes which take place in the species ratio I have included in Table 23 

 (derived from the International Statistics) the percentage for each month in the whole 

 period 1927-35. From 1935 onwards, hardly a whale was taken before the beginning of 

 November or after the end of March, and separate figures are therefore shown for 

 1938-9 which is the most recent season for which I have particulars. Table 23 (a) is 

 based on a total of 159,674 whales, and (b) on 36,665 whales. The figures for September 

 are based on very few whales. Those for May are misleading, for here most of the 

 whales were Sei and may have been taken on the way home after the ships had left the 

 normal whaling grounds. It is therefore not to be supposed that the May figures have 

 much to do with the species ratio on the Antarctic grounds. 



Table 23. Antarctic pelagic catches. Monthly percentage of each species 



Total catch 



Blue 



Fin 



Sei 



Hump- 

 back 



Sperm 



Per cent 



Blue 



Fin 



Sei 



Hump- 

 back 



Sperm 



September 



October 



November 



December 



January 



February 



March 



April 



May 



November 



December 



January 



February 



March 



74 

 6,772 

 23.570 

 32,718 

 23,081 

 14,814 



7.644 

 644 



5 



846 

 5.124 

 4.899 

 2,368 



602 



(a) Eight seasons, 1927-35 



03 



1-7 

 09 



i-3 

 04 

 01 



22'9 



94 

 4-2 

 50 

 6-6 



Table 24 shows the South Georgia catches during the same period. The statistics 

 show only four whales taken in May since 1927, and this month is therefore omitted. 



It is clear from Table 23 that in the Antarctic the proportion of Blue whales caught 

 declines while that of Fin whales increases. The International Statistics show that this 



