iqs discovery reports 



South Georgia whaling grounds, where spawning it seems (p. 190) is of negligible account, we are 

 left with the shelf water of the Bransfield Strait and the shelf and oceanic water of the western 

 Weddell drift as being to all appearances the main locus of the spawning krill. Since, however, in 

 spite of the abundance of spent females in the oceanic water of the western Weddell drift, there is no 

 satisfactory evidence (p. 189), either from the surface or the deeper layers, that it is in or over deep 

 water that they actually lay their eggs, it is difficult to avoid the conclusion, already alluded to on p. 189, 

 that the spent females found for instance between the South Orkneys and the South Sandwich Islands 

 (Fig. 25), and doubtless those at South Georgia as well, get carried there as spent females in the 

 surface drift, having laid their eggs some time before somewhere to the westward of where they were 

 captured. In other words, highly localised, in terms of Antarctica as a whole, as the Bransfield Strait- 

 Weddell West region may be said to be, it would appear that, disregarding for the moment the obvious 

 potentialities of the East Wind drift, in the Atlantic sector the spawning of the krill, in its major 

 aspects, might well be confined to within still narrower geographical limits, and be in fact the pheno- 

 menon, the remarkable thing, I have suggested it to be, a phenomenon peculiar, perhaps for all 

 practical purposes exclusive, to the shallow shelf and slope waters that in this sector lie in the far 

 western and south-western reaches of the Weddell drift. 



The region of circumscribed spawning to which our evidence seems to point is not an easy one 

 to explore and perhaps for long, if not always, will remain undefined, the south-western reaches 

 of the Weddell drift being particularly difficult and hazardous of access owing to the piling up of 

 the pack-ice there. Further exploration, however, in the more readily accessible westerly reaches 

 of the current, for instance, in the extensive area of shelf water lying to the south of the South 

 Orkney Islands and in the shallow water associated with the Clarence Island-South Orkneys and 

 South Orkneys-South Sandwich Islands ridges, might reveal that they too are involved in the 

 spawning. 



The distribution of the larvae that reach the surface in summer (January-March), those, that is, 

 that have but recently accomplished the long developmental ascent, provides perhaps the most con- 

 vincing evidence we have (Figs. 26 and 27) that somewhere not far from where I have supposed it to 

 lie there must exist a relatively discrete spawning area where eggs are deposited on an immense scale, 

 a scale, moreover, to all appearances incomparably greater than anything to be found elsewhere in 

 these far southern waters. Fig. 26 shows the summer distribution of the Calyptopes and Furcilias 

 based on the surface (0-5 m.) gatherings of the towed stramin nets, and while the catch-figures in- 

 volved in its construction include very few of the First Calyptopis, a stage which owing to its small size 

 (p. 360) readily escapes through the meshes of the stramin net, it nevertheless presents a most striking 

 picture of the major spawning that seems to be taking place somewhere in the western part of the 

 Weddell Sea. 



The summer distribution of the recent risings based on the material from the vertical nets, in which 

 the First Calyptopis is always well represented, is shown for comparison in Fig. 27, and here 

 again the emphasis is on Weddell West as being to all appearances, in the northern zone at any rate, 

 the principal locus of the spawning krill. It must be significant, too, that throughout March, when the 

 vast majority of the eggs have probably been laid, in Weddell West, but there alone, we struck the 

 larvae at one level or another in our vertical hauls at every station zve made. It is true that in 

 April (p. 311, Fig. 75) we find something rather different, for then we have the Calyptopes well 

 represented as far east as 0° and 20° E in Weddell East. These late risings to the east, however, will 

 be dealt with later (see pp. 313-14). Fig. 27, however, points clearly to the existence of another, 

 perhaps secondary, spawning ground in the coastal waters of the East Wind drift, a spawning ground 

 which, oddly it would seem, the stramin nets with their much greater catching capacity completely fail 



