DISTRIBUTION OF ANTARCTIC MACROPLANKTON 153 



out of the Weddell Sea, on the other hand, impinges on the loop of the Scotia arc, and 

 although the hydrological conditions in this region have not yet been worked out in 

 detail, there can be little doubt that there are disturbances in the speed and direction 

 of the currents. The most variable and fluctuating macroplankton was found, as we 

 have seen, to the east of the South Sandwich Islands, and this is just where we should 

 expect to find disturbances and eddies in the water, like the eddies formed in a river on 

 the downstream side of a ford or the piers of a bridge. In the eastern Weddell Sea, 

 where the drift of the water is undisturbed, we find again a uniform plankton popula- 

 tion. Much of this area, as it is shown in Fig. 1, must contain water which is flowing 

 westwards in the counter-current which is known to exist in the high latitudes, but the 

 point at which the heterogeneous plankton of the old Weddell water changes to the 

 homogeneous plankton of the eastern Weddell Sea (i.e. between WS 543 and WS 544), 

 does not necessarily mark the division between the easterly and the westerly drift. 



THE MACROPLANKTON AND THE 

 DISTRIBUTION OF WHALES 



It need hardly be pointed out that no immediate solution of the problem of the dis- 

 tribution of whales can be sought in a study of the general distribution of the macro- 

 plankton of the waters in which they live. A more direct connection no doubt exists 

 between the movements of whales on the one hand and the distribution of " krill " and 

 the hydrological conditions on the other hand. What we can hope for in a study of the 

 associated plankton population is something in the nature of a symptom of the environ- 

 mental conditions which are most favourable to the concentration of whales. The 

 subject will not be pursued very far at the present stage, but it is worth while to mention 

 one or two facts which suggest a link between the behaviour of whales and the distri- 

 bution of the macroplankton in general. 



The question is very difficult to approach because the movements and distribution 

 of whales are influenced by more than one factor of major importance. It is known that 

 they are migratory animals, visiting the warmer waters for purposes of breeding, and 

 seeking their food in the cold waters of the Antarctic. We might assume then that the 

 presence of a large concentration of whales in a particular place is to be explained on the 

 grounds either that the whales have found there the environment which they require, 

 or that they are on the way to, or looking for such an environment. The difficulty is to 

 know which. 



Around South Georgia and the South Shetland and South Orkney Islands whaling 

 has been in progress for many years, and since the modern development of the factory 

 ship the areas within which whales are caught has been vastly extended. The positions 

 of the whaling grounds in the Atlantic sector of the Antarctic (as well as in other sectors) 

 has been defined in recent papers by Hjort, Lie and Ruud (1932 and 1933). The charts 

 published by these authors (1932, chart no. 1 ; 1933, pis. i, ii, v and vi), show that, 

 though important changes take place during the season, most of the whaling in the 



