68 DISCOVERY REPORTS 



Table 2. Relative abundance of E. superba at the ice-edge and in the open sea in the southern or East 



Wind zone. Numbers of net hauls upon which annual averages are based are shown in parentheses {For 



corrections, see pp. 282-3) 



Number of 

 Under 16 mm. 16-20 mm. Over 20 mm. net hauls 



Month Ice-edge Open sea Ice-edge Open sea Ice-edge Open sea Ice-edge Open sea 



Summer 



Dec. 17 — II 12 26 257 2 6 



Jan. 9 10 33 72 280 236 10 72 



Feb. 1 — 22 I 710 863 12 73 



Seasonal average 6 5 26 35 474 540 24 151 



Autumn 



March — 2 125 31 1147 354 10 56 



April-May 378 41 14 — 717 225 6 21 



Seasonal average 142 12 84 22 986 318 16 77 



Annual averages 



Under 16 mm. 16-20 mm. Over 20 mm. 



Ice-edge Open sea Ice-edge Open sea Ice-edge Open sea 



378 41 58 34 679 465 



(6) (21) (32) (201) (40) (228) 



Observations in the eastern part of the Weddell drift, repeated in practically the same positions 



at different times of the year, throw much new light on the real extent of the association of the krill 



with the Antarctic pack. At Station 2316, for example, in 57° 15-5' S, 01° 13-4' E, 58,488 larval krill, 



the vast majority Second Calyptopes, were taken in the surface net on 14 April 1938, the ice-edge 



at this time lying in 65° S, well inside the northern boundary of the East Wind drift, and more than 



460 miles due south. The larvae continued to be taken in enormous numbers in the ice-free water 



southward of Station 2316, their abundance ceasing abruptly south of Station 2320 in 61° io-6' S, 



00° 437' E, the combined catches at Stations 2321, 2322 and 2323, the last at the ice-edge itself, 



amounting to only twenty-eight individuals in all. The larvae are thus seen to have been concentrated 



in a belt of open water some 250 miles wide, a fact which incidentally provides a useful indication of 



the probable minimum width of the Weddell stream in this particular meridian. Approximately a 



month and a half later, although not in the same year, another station was made very close to the 



position of Station 2316 — Station 1781 on 2 June 1936, 57° 41-8' S, 00° 19-8' W — where over 



10,000 larvae, Furcilias 1-4, were taken in the surface net. As the winter was now well advanced the 



whole of the richly populated area traversed in April 1938 had become frozen over, and Station 1781, 



instead of being in open water as it would have been had it occurred earlier in the year, lay among 



the scattered young floes at the edge of an ice-field that stretched unbroken to the south. Later in 



1938, on 18 August, a second station. Station 2394, was made at the ice-edge in 57° 18-5' S, 00° 52-2' E, 



a position little more than ten miles away from that of Station 2316, 14,976 young krill, Furcilia 6 



and very young adolescents, being taken, as before in the surface net. 



Repeated observations in more easterly parts of the drift reveal a similar situation. At Station 2344 

 in 56° 18-4' S, 19° 32-6' E, 35,520 larvae, principally Furcilias 1-3, were taken on 26 April 1938 

 with the ice-edge lying in 67° S, again deep inside the East Wind zone and more than 640 miles to 

 the south. Very few larvae were taken at ten stations made southward of Station 2344, and only two 

 at the ice-edge itself. The mass of the larvae in this meridian were confined to a belt of open water 



