i86 DISCOVERY REPORTS 



March for Fin whales. Blue whales were scarce in February and March and Fin whales 

 in February, facts which are also indicated in Plates XXVIII and XXXVI. In this 

 season at least there are grounds for believing that the whales travelled south beyond the 

 whaling area and again passed through it on their return to the north. 



The year 1925-6, as Harmer has pointed out, was clearly an exceptional one: it is 

 only in this season that a bimodal graph is found in both the species. But there is some 

 reason for supposing that it is only in exceptional conditions that whale movements can 

 be indicated by the available data. Though we have little exact information on the 

 behaviour of whales which visit the South Shetlands, it may be assumed that they do not 

 diifer appreciably from those at South Georgia. The whales, no doubt, do not arrive in a 

 regular flow, but appear from time to time, in schools of greater or less concentration in 

 which one or other sex may predominate. Schools which arrive first will probably 

 travel farthest and in a normal year some of them, which have passed beyond the 

 whaling limits, will be replaced by later arrivals from the north. If this view is correct 

 the indications to be derived from monthly charts of distribution must necessarily be 

 blurred and indistinct ; and since the whalers pursue their quarry along several hundred 

 miles of coast-line, statistics will usually give no hint of movement. Only in an ex- 

 ceptional season, when the greater part of the stock is for a time inaccessible to the 

 whalers, can we hope to obtain precise information. 



In the season 1925-6 the whalers penetrated south-west as far as the Biscoe Archi- 

 pelago, and here, in December, they obtained a few Blue whales. That they went so far 

 is evidence that the pack-ice lay well to the south and that whales were not abundant to 

 the north. During the period under review there is only one other season when the 

 whalers extended their operations so far to the south-west. This was in season 1923-4, 

 when both Blue and Fin whales were taken in some numbers at the extreme south- 

 western limit of the area (Plates XXVI, XXXIV). It is to be imagined that in this season 

 also the pack-ice lay far to the south and one would expect, therefore, that the monthly 

 catches would show early and late maxima as in 1925-6. The statistics given by Harmer 

 indicate that Blue whales reached their peak in December and Fin whales in January 

 and February, but in neither species did a second maximum occur. The absence of the 

 second peak is perhaps to be attributed to unusual whale movements at the end of the 

 season. In 1923-4 the customary autumn concentration in Bransfield Strait did not 

 occur, and it appears that the whales took a different route when leaving the grounds, 

 perhaps going due north from Smith Island. 



The charts for the individual seasons indicate that the movements of the whale 

 schools may differ rather considerably. If the grounds are not approached directly from 

 the north (when whales first appear oflr Smith Island), they are generally taken in the 

 early months of the season at the northern end of Bransfield Strait and pass through the 

 strait on their passage south. This is to be seen for Fin whales in 1924-5 and 1925-6 

 (Plates XXVII, XXVIII), and for Blue whales in 1922-3 and 1925-6 (Plates XXXIII 

 and XXXVI). Occasionally, however, as in Fin whales, 1926-7 and 1927-8 (Plates 

 XXIX, XXX), and in Blue whales 1926-7 (Plate XXXVII), they appear to have avoided 



