THE BLUBBER OF WHALES 



369 



At Saldanha Bay a decrease in blubber thickness among the mature whales balances 

 the increase shown at South Georgia in both species. The immature whales are again 

 thinner than the normal. 



OCT. NOV. 



< 



-1 r- r 



DEC. JAN. FEB. 

 —SOUTH GEORGIA- 



MAR 



APR. 



> 



MAY 



T r 



JUNE JULY AUG. SEPT. 

 -« SOUTH AFRICA 



OCT 



— >■ 



Fig. 105. Male Fin whales. Monthly average thickness of blubber. 

 (Separate curves for 1925-6 and 1926-7 seasons.) 



Whales more than 20-0 ni. long. 



Whales less than i8-o m. long. 



Mo 



i-)U 



OCT. NOV. 

 < 



-r 



DEC. JAN. FEB. MAR. 

 SOUTH GEORGIA 



1 1 1 r 



APR. MAY JUNE JULY AUG. SEPT. OCT 

 »• ■« SOUTH AFRICA »• 



Fig. 106. Male Blue whales. Monthly average thickness of blubber. 

 — Whales more than 23-0 m. long. Whales less than 19-0 m. long. 



The similarity of the results obtained for the males and resting females indicates the 

 general conclusion that whales are fatter at the end of the season at South Georgia 

 than they are at the beginning and that a decrease in blubber thickness takes place 

 in South African waters. The increase in average blubber thickness of adult whales at 

 South Georgia should be due to good feeding and fattening in that neighbourhood, 

 where the food, as already explained, is available in abundance. The possibility might 

 be suggested that the increase in fatness may be due to increasing numbers of fat whales 

 arriving in South Georgian waters from other, apparently richer, feeding grounds as 



15 



