74 DISCOVERY REPORTS 



Eraser's findings, that no krill should have been encountered except at Station WS 542, at the northern 

 end of the line. On looking into the matter, however, I have since found from the records of krill 

 patches kept on board, and the examination of certain other nets fished on this cruise which Fraser 

 could not have looked at, that there was in fact krill in considerable abundance along a substantial 

 part of the route from Station WS 542 southwards to Station WS 547 in 62° 40' S, 17° 02' W, the 

 gatherings including one enormous haul of over 10,000 individuals at Station WS 546 in 62° 09' S, 

 17° 12' W. Moreover, confirmed krill patches were seen at Station WS 546 and in great profusion 

 between Stations WS 555 in 60° 27' S, 19° 36' W and WS 559 in 57° 19' S, 24° 50' W, pointing 

 to the pronounced abundance of the whale food along the route traversed. 



However, even if there had been no krill in this supposedly normally ice-covered sea, the suggestion that 

 their absence could be due to a deliberate migration in quest of better grazing seems rather speculative. 



In the other regions of heavy, more or less permanent, pack we have only a single observation from 

 the Ross Sea in December 1928, Station RS 9 in 70° 02' S, 180° 10' W, located deep inside an ice- 

 belt some 270 miles wide which stretched in this meridian from 68° to 70° 30' S. A meagre catch, 

 consisting of forty-six Furcilia 6 and adolescents up to 20 mm. long, and eleven older adolescents up 

 to 30 mm., was obtained in the horizontal surface net. As this station was made in broad daylight, 

 however, and the towing on the surface, and because in broad daylight the older krill so readily avoid 

 the surface net, the catch of the smaller animals only, those up to 20 mm. long, can be taken as in any 

 way indicative of the poverty of the whale food we seem to have recorded there. While it would be 

 unwise, therefore, to draw any definite conclusion from this one observation, it is perhaps worth 

 while mentioning that the total yield of eleven towings made by the ' Terra Nova ' in this ice-belt in 

 December 1910, along approximately the same meridian, and between latitudes 66° and 72° S, was 

 only two individuals (Harmer and Lillie, 1914; Tattersall, 1924). 



There are no observations deep inside the great ice-belt in the Pacific sector. As Mackintosh and 

 Herdman (1940) remark, the ice there seems 'stagnant and no ship has penetrated it to the land, 

 although several have attempted to do so '.^ 



While there may be some grounds for believing that an eddy, or area of slack or ' dead ' water, deep 

 inside the permanent ice of the Weddell Sea may partly be responsible for the apparent scarcity of 

 the whale food there, it is still possible that the scarcity may not after all be a real one, for in the still, 

 almost crystal-clear water of the pack and the continuous summer daylight of these high latitudes the 

 krill may see and avoid the surface nets, both horizontal and oblique, far more readily than they can 

 in the more turbid, diatom-rich and boisterous conditions of the open sea. Griffith Taylor (1916) for 

 instance calls attention to the wealth of Euphausia in the open water between the ice-floes at the 

 approaches to the Ross Sea, where, he notes, owing to their large size, they can readily be seen from 

 the decks of vessels. In small pools deep inside the pack-ice off the Princess Astrid Coast Wild (1923) 

 reports a similar abundance. 



Finally, it may be noted, the underlying implication of the remarks of Ruud and Fraser quoted at 

 the beginning of this section is that it is in the pack or at its edge that the krill, especially the late larval 

 and early adolescent krill, find the most suitable conditions for their growth and development. It will 

 be shown conclusively later however (p. 355, Fig. 107) that the ice-edge and pack-ice generally, far 

 from being the most suitable environment for this species, particularly when in its larval or adolescent 

 state, is in fact a distinctly unfavourable one, slowing up the growth rate and retarding the develop- 

 ment to a quite unmistakable degree. It may be noted too that the adult ice-edge scarcity reported 

 by John (p. 65) during the April to November circumpolar cruise, a scarcity Tables i and 2 most 

 emphatically contradict, can now be readily explained. For with a single exception all the ice-edge 



• Though see p. 51, note i. 



