-28- 



larger diatoms were present were mostly devoid of krill. There- 

 fore, Kawamura suggested that krill move to reach or remain in 

 areas where preferred foods are located. Pavlov (1971, 1974) 

 has shown that krill can feed on detritus, allowing them to feed 

 throughout the year. 



B. Antarctic Whales 



Southern Ocean whale stocks, once abundant and diverse, 

 supported the world's largest whale fishery eventually leading 

 to their marked decline. As large-scale fisheries for other 

 Southern Ocean living resources are considered, the role of 

 whales is again central to discussions regarding ecosystem inter- 

 actions. Several reviews of Southern Ocean whales have been 

 published (Mackintosh, 1970, 1972a; Gambell, 1973, 1976e; 

 Laws, 1977a, 1977b; Nishiwaki, 1977). A great deal is known 

 about the great whales because of their commercial importance. 

 Moreover, because of their large individual and population bio- 

 mass, their role in the trophodynamics of the marine ecosystem 

 and their direct relationship to krill are of major significance, 

 Hence, the following comments deal principally with baleen 

 species including: sei, fin, blue, humpback, and minke whales. 

 Sperm whales and some of the smaller odontocetes will be 

 mentioned when available information is appropriate to the 

 discussion. The following section reviews information on the 

 distribution, movements, standing stock, stock identification, 

 and food habits of the whales of the Southern Ocean, both 

 before and after major exploitation earlier in this century. 



1. B aleen Whales 



a. Distribution 



Mackintosh (1973) investigated seasonal variations in the 

 location of Antarctic whaling grounds. Figure 9 shows the 

 principal summer feeding areas for Antarctic baleen whales. 

 The relationship between Euphausiid and vertebrate species 

 distribution in the Antarctic is shown in Figure 6. 



Although baleen whales generally have a circumpolar distri- 

 bution, latitudinal differences between species exist since some 

 whales travel farther south to feed than others. For example, 

 blue whales and minke whales concentrate between 60° S. and 

 70° S., fin whales are most highly concentrated while feeding 

 from 50° S. to 60° S., sei whales are mostly found from 40° S. 

 to 50° S., pigmy blue whales rarely are found south of 54° S., 

 and southern right whales mostly inhabit subantarctic waters 

 between 30° S. and 50° S. year-around (Taylor, 1957; Ichihara, 

 1966; Ohsumi et al., 1970; Laws, 1977a). In addition to 

 partitioning feeding grounds by species, whales also demonstrate 



