284 DISCOVERY REPORTS 



in the Azores show marked seasonal changes both in quantity and constitution. These changes, 

 coupled with the fact that no foetuses of middle size have been recovered from pregnant whales 

 (Table 21, p. 268), must reflect a movement to and from the islands. 



The catch curves show that, whilst whaling in the Azores is conducted in all months of the year, 

 most of the whales are caught in summer. However, it is well to remember that whales are likely to 

 be more plentiful in winter than is suggested by the small catches of this season, because the winter 

 rains and gales may defeat the cliff look-outs and keep the whaleboats on shore. The winter catches are 

 nearly all males: only twenty-four females were among the 199 whales caught between November and 

 May in 1939-54 (Table 29). It appears that, save for one or two large, possibly aged stragglers (Table 31), 



Fig. 13. Monthly catches at Horta 

 from 1939 to 1954. 



Fig. 14. Monthly catches in the Azores 

 for 1949, 1951 and 1952. 



the female stock have left the Azores by November and do not begin to return until May, reaching 

 Fayal in June. The minor fraction of the male stock exploited in winter is thought to be mostly dis- 

 posed in schools (p. 279), and comprises animals which are practically all sexually mature, indeed, 

 those recorded from the greater part of winter (January to May) are all mature (Table 31). It may be 

 that the winter males are moving into the Azores from elsewhere, but it is perhaps more reasonable 

 to suppose that they are a fraction of the stock which winters around the islands and does not take 

 part in the emigration of the end of summer. So far as the catch curves may reflect the movements of 

 the population, it appears that the main stock, that is, the females and the major part of the males, 

 returns to the Azores at the beginning of summer and achieves its greatest strength in July. The catches 

 decline in subsequent months, when the whales are considered to be emigrating. The proportion of 

 immature males is highest when the catches are at their peak in July: the highest proportion of imma- 

 ture females occurs in September, perhaps because some of the older, larger females may leave the 



