THE HUMPBACK WHALE 



79 



Similar north and south migrations are known to occur on the coasts of South 

 America though figures are not available to illustrate them. In the French Congo, 

 nearly on the equator, according to Harmer (1931), the season graph is unimodal (July- 

 August), and the reason suggested for this is that the Congo region represents the 

 northern limit of the migration and is visited, but not passed, by the Humpbacks. 

 Similarly Olsen (1914-15) shows that the season graph at Linga Linga, Inhambane, 

 Portuguese East Africa (23-30° S), is unimodal for the same reason. 



Turning now to southern localities. Fig. 80 shows the season graph for seasons 19 15-16 

 and 1916-17 at South Georgia, and 1923-4 and 1925-6 at South Shetland. Humpbacks 



01 ZOO- 

 _aj 



JZ 



o 



CD 



n 100- 



— South Georgia 

 -- 5outh Shetland 



Fig. 80. Humpback whale. Monthly catches at South Georgia for seasons 1915-16 and 1916-17, and at 



South Shetlands for seasons 1923-4 and 1925-6. 



have not formed an important part of the catch since those years in South Georgia, and 

 consequently the figures are very scanty for later seasons and are not included here. 

 This graph again is bimodal, with the first peak in January and a second smaller one in 

 May. The first peak undoubtedly represents the arrival of the whales on their migration 

 from the north, and the second one may represent the latter part of the return migration 

 from further south. The season graph for the South Shetlands is, however, unimodal, 

 from which the conclusion may be drawn that this region represents the southern limit 

 of the migration. 



It must be remembered, however, that the migration towards the north does not in- 

 clude all Humpback whales, because up to the season 1917-18 several of the whaling 



