RORQUALS OR FIN WHALES 221 



northern summei of 1935, this species has been taken by 

 whaling enterprises in the Faroe Islands, Iceland, Alaska, 

 Kamchatka, Japan, Mexico, Chile, California and South 

 Africa ; but during that time nearly 94 per cent, of a total 

 world catch of nearly 17,000 came from the Antarctic alone. 



The Blue Whate feeds almost exclusively on shrimp-like 

 animals called Euphausians or, by the whalers, Krill. One 

 kind of Krill is found in northern waters and another, a 

 southern form, in the Antarctic. Southern Krill occurs in 

 immense shoals in the seas surrounding the Antarctic continent, 

 and it is no uncommon sight to see whales and large perch-like 

 fish devouring the Krill from below the surface of the water, 

 and hosts of sea-birds — Giant Petrels, Cape Pigeons and Whale- 

 birds — swooping down from above. This shrimp is a key 

 organism in the economy of Antarctic life, for not only does it 

 provide food for whales, fishes and the birds mentioned, but 

 certain species of penguin and at least one species of seal are 

 entirely dependent on its abundance. 



The device for straining the food-charged water is the same 

 in the Blue as in the Right Whale, but whereas the lower 

 jaws of the latter animal are used as a kind of scoop to 

 collect plankton, in the Blue Whale and other Rorquals the 

 external grooving of the throat probably allows distension of 

 that region so that water flows into the mouth and into the 

 cavity formed by the distension. Subsequent contraction of 

 the muscles expels the water through the whalebone plates, 

 leaving the food deposited on the matted fringes. 



The Blue Whale migrates annually in a general northerly 

 and southerly direction, but these movements tend at times 

 to be obscured by subsidiary migrations resulting from varia- 

 tions in local conditions. Nevertheless, as Mackintosh and 

 Wheeler say in their 'Southern Blue and Fin Whales', "it 

 may be mentioned here that there is a general movement 

 northwards into warmer waters for breeding during the 

 southern winter and southwards for feeding during the southern 

 summer ". Subtropical waters contain very little whale food, 

 but, as we have already mentioned, Krill is abundant in the 

 Antarctic seas, and thither the whales go to consume it. Most 

 of the whales taken in low latitudes are thin and ill-fed, 

 whereas those that have been in the Antarctic for some time 



