2io DISCOVERY REPORTS 



usually in large quantities. Occasionally we found a fish or two among the krill ; apart from this 

 we did not find anything but Euphausia superba. 



It will be seen from the chart of our positions that the bulk of our catch was made far from land 

 and known banks, but always in close proximity to the pack-ice. Our whalers always tried to follow 

 the drifting ice, partly in order to be in water which was calm enough for handling the carcases, and 

 partly because the blue whale prefers to frequent the edge of the ice or even the larger lanes between 

 the pack-ice. Evidently, therefore, there must be great quantities of krill out at sea among the 

 icebergs and drifting floes, and not chiefly near land and coastal banks as suggested by Mackintosh 

 and Wheeler. . . . 



E. superba, as will shortly be described, occurred abundantly off the north-east coast 

 of South Georgia, both in March 1926 and in December and January 1926-7. The 

 relation of its distribution to that of the whale fishery at the time of our surveys is dis- 

 cussed in a special section on p. 273 . That it is not evenly distributed through the water is 

 clearly shown by the two series of consecutive net hauls which were taken off the north- 

 east coast of South Georgia in January, 1927. These are described on p. 254 and illus- 

 trated in Fig. 134. It is seen to occur in dense patches, not more than half a mile across 

 and in all probability less than 200 yards across, and patches which are fairly evenly 

 separated from one another by gaps of over half a mile. This concentration of the 

 Euphausians into small densely crowded areas helps one to understand how the large 

 rorquals are able to collect sufficient to form an ample meal. Mackintosh and Wheeler 

 (1929) make an interesting observation in this connection in commenting on the krill 

 found in the stomachs during the 1926-7 season. They state that: 



. . . The krill differed from that of other seasons in the fact that there was in most cases a noticeable 

 mixing of Euphausiids of different sizes. These were not always mixed indiscriminately in the 

 stomach. Large or small individuals might be found together in different parts of the mass of 

 stomach contents, or patches of large ones might occur in a mass of smaller forms, suggesting that the 

 whale had been feeding on separate shoals which differed in respect of the sizes of the individuals. . . . 



On more than one occasion we saw a dense swarm of young E. superba in Cumberland 

 Bay, South Georgia. We will quote from a journal written (by A.C.H.) at the time: 



. . . For a whole day there was a dense swarm, like a red cloud, of closely-packed Euphausians 

 {Euphausia superba) against the jetty at our shore station. There must have been thousands and 

 thousands in a close swarm some four feet across. They were all swimming hard and going round and 

 round, sometimes in a circular course, sometimes in a ' figure 8 ', but never breaking away from the 

 one mass. The cloud would sometimes change shape, elongate this way or that. (There appeared to 

 be some guiding ' principle ' — almost as if there was some leader in command of the whole !) At times 

 they would form into two such moving parties and one would tend to separate from the other, so that 

 the swarm became dumb-bell shaped ; but as soon as the connecting link became of a certain thinness 

 the one part would turn back and flow into the other to form one big swarm again. It was drawn into 

 the whole like the pseudopodium of an amoeba ; indeed the whole swarm appeared to behave as one 

 large organism. It was for the most part at the surface, but at times the whole would sink down almost 

 out of sight to rise again. This would happen apparently spontaneously, or again happen if some 

 sudden disturbance occurred, the approach of a boat for instance. They were so close to the pier, at 

 times even below it, that one could look straight down on to them and observe them with ease. I put 

 in my walking stick and stirred the whole swarm up quickly so as to scatter them in all directions ; but 

 within half a minute they were all back again in their old formation. 



