282 DISCOVERY REPORTS 



DISTRIBUTION AND SEASONAL MOVEMENTS 

 That sperm whales are plentiful round the Azores is shown by the contribution the islands make to 

 the world catch. Table 30 and Fig. 12 compare the Azores and world catches for the period 1910-53. 

 The table and figure give no clue to what fraction of the world stock of sperm whales frequents the 

 Azores : they rather betray the vagaries of sperm whaling, such as the fluctuating demand for sperm 

 oil in peace and war, and the exploitation of new grounds for steam whaling. But the table does show 

 that over a period of forty-three years the shore fishery of this small archipelago, hunting with hand 

 harpoons from open boats of limited range, has accounted for 8-64% of the world catch of 151,699 

 sperm whales. This indicates the presence of a fair stock of whales round the Azores. 



Local distribution 

 Concerning the area frequented by the stock one may only quote Wilkes who said that the Western 

 Islands Ground did not extend more than two hundred miles from the islands and lay principally to the 

 south of them (1845, v, p. 520). 



The whales caught by the islanders are sighted at three to thirty miles from the coast. It is interest- 

 ing that some part of the stock has this coastal habit, because the sperm whale is generally considered 

 to frequent the open ocean far from land. When sperm whales are found close to the coast the region 

 seems to be one where vulcanism or other cataclysm has raised the land sheer from the depths : here 

 the sperm whale may approach the coast yet still retain a depth of water below. Such regions are the 

 coasts of Chile and Peru and the coasts of oceanic islands. Thus, in the Azores, depths of several 

 hundred fathoms may be encountered within a mile of the coast. Many of the old-time sperm whaling 

 grounds were oceanic islands where whaling was often conducted in sight of the shore. From Towns- 

 end's charts (1935, showing the positions of sperm whales taken by American whaleships 1761-1920), 

 from the earlier whale charts of Maury (1852) and Bolau (1896), and from the nineteenth-century 

 narratives (Beale, 1839, ch. xv; Wilkes, 1845, v, p. 517 ff. ; Scammon, 1874, p. 214 ff. ; and Clark, 

 1887, p. 8 ff.) it is possible to count some thirty-five archipelagoes or isolated islands noted for sperm 

 whaling and distributed through all the oceans. Of all these, only the Azores, Madeira, and the 

 Bonin Islands are still exploited, the Bonin Islands by Japanese steam whaling. It has been suggested 

 that the sperm whale is especially attracted to oceanic islands, and attempts have been made to explain 

 the attraction. Colnett (1798, p. 147), McKenzie (in Maury, 1852, p. 238) and Seabury (in Clark, 

 1887, p. 10) believed that sperm whales came to the Galapagos Islands to calve. Wilkes (1845, p. 512) 

 and Maury (1874, p. 59) believed that food was more plentiful off oceanic islands, saying, by way of 

 illustration, that food brought in oceanic currents accumulated round the Azores. 



The haunts of the old whaleships are not perhaps sufficient evidence to say categorically that sperm 

 whales especially frequent the neighbourhood of oceanic islands. Yet it may well be that the food 

 supply around them is enhanced; that, other things being equal, the upthrust of volcanic peaks — 

 interrupting a wide and deep water column — presumably causes some vertical mixing which breaks 

 down the discontinuity layer and allows local increase in organic production. It has at least been 

 shown (p. 262) that around the Azores there is certainly a substantial food supply for the sperm whale. 



Seasonal changes 

 Fig. 13 shows the monthly catches of male and female sperm whales at Fayal from 1939 to 1953. That 

 these curves for Fayal are in general representative of the whole archipelago is seen by comparing 

 Fig. 1 4 which shows the catches for those years (1949, 195 1 and 1952) where aggregate Azores statistics 

 are available to me. It is clear from Figs. 13 and 14, and from the sex ratios in Table 29, that the catches 



