THE SEI WHALE 



273 



can be given until further information is available, but it is suggested that it may be 

 connected with the variations from year to year in the ocean currents of these regions. 

 It must be remembered, hovv^ever, that the numbers of Sei whales taken in any season 

 depend partly on the numbers of other species available to the whalers. Further the 

 Sei whale has been almost notorious for suddenly appearing in large numbers on whaling 

 grounds where it was previously scarce. For instance, it is said to have appeared 

 at South Georgia for the first time in season 1913-14; and to have first arrived in great 

 numbers off the Hebrides and Shetlands in the northern hemisphere in 1906. But it 

 appears possible that the accounts of these sudden appearances are based on inac- 



Apr 



MdL| ' Jun ■ Jul Aug ' Sep Oct 



Fig. 108. Sei whale. Monthly catches at Natal, 1918-26. 



Nov 



curate observation. In the early days of whaling at South Georgia, Right whales and 

 Humpbacks were so plentiful that the comparatively low powered catchers had no cause 

 to seek for whales at any great distance from the whaling stations. The reason for the 

 sudden abundance of Sei whales at the Scottish whaling stations is given by Haldane 

 (1909) as the extension of fishing outside a previous 40-mile limit. He says, "B. borealts 

 was more abundant, B. nmsciihis scarcer than last year ; the reason given for this is that 

 during the time of the 40-mile limit there were plenty of B. musculus within the limit, 

 doubtless feeding on the herring which were abundant on the west coast of Shetland, 

 while beyond the 40 miles B. borealts were plentiful and B. musailus not so numerous." 

 In both these localities, then, the apparent abundance may have been due merely to 



