332 DISCOVERY REPORTS 



predominated in the upper nets, and in the lower nets adults and stage v appeared to 

 predominate in about equal proportions. The predominance of adults in the lower nets 

 at these stations, however, is largely due to the increased proportion of adult males. 



Thus the Rhincalanus population of the Bellingshausen Sea current, when it became 

 carried into the colder Weddell Sea water where the temperature was below o° C, 

 appears either to have been prevented from reaching maturity by the middle of January, 

 as at Sts. 795, 798, 806, and 808, or, as at Sts. 763, 765, 768 and 779, to have reached 

 maturity but failed to spawn. 



At the stations in Weddell Sea water containing melting or recently melted pack-ice 

 (- 1-5-0° C.) the stock consisted mostly of adults with varying proportions of stage v. At 

 j3nly two stations did stage v predominate (Sts. 809 and 815), but at these the size of the 

 catches was possibly too small to give accurate percentages. At St. 804 a fair proportion 

 of stage iv was taken, possibly carried southwards in Atlantic deep water. At all these 

 stations in Weddell Sea water with a temperature below 0° C. it seems probable, from 

 the complete absence of young stages, that we are dealing with a population which had 

 failed to spawn, and at Sts. 810, 812, 822 and 823 — the most centrally situated in the 

 Weddell Sea — the scarcity of stages younger than stage vi (adult) is very striking. The 

 population in this water (less than 0° C.) is being carried northwards out of the Weddell 

 Sea in the north-easterly current, and it may be suggested that this is an over-wintered 

 stock, resulting from the previous winter's spawning, which was carried into the 

 Weddell Sea by warm deep water of the East Wind Drift. 



Finally we come to the stations in the East Wind Drift current flowing westwards into 

 the Weddell Sea south of 66° S (Sts. 815, 816 and 817). We find that the stock at these 

 three stations consisted of stages iv (at Sts. 816 and 817) and stage v (at St. 815). Further, 

 the catches were entirely in the lower nets. This is a population which, from its age, 

 must have been spawned earlier on during the current summer somewhere to the east 

 off the coast of Coats Land. At any rate, since there are no signs of a parent generation, 

 it is reasonable to suppose that this stock had been spawned a considerable distance away, 

 perhaps outside the Weddell Sea ; that it was the same stock, therefore, as that found 

 at Sts. 796, 802 and 803 and that it had been carried into the Weddell Sea by the 

 westward-flowing warm deep water of the East Wind Drift current originating in the 

 South Indian Ocean. It thus seems probable that the population at Sts. 810, 812, 822, 

 823 and perhaps 780 consisted of a similar stock carried into the Weddell Sea during 

 the preceding winter or even during the previous season, and the adults of which this 

 stock consisted must have been over six months or perhaps over a year old. 



Weddell Sea and Eastern Scotia Sea, end of January 1932 (Fig. 23, Table VI c) 



At St. 824 (27. i. 23 ; Fig. i b) we again encounter a stock which was probably of mixed 

 origin, as was suggested for the population in this region during December (Sts. 766- 

 768, p. 330). It probably originated partly from the Bellingshausen Sea water of the 

 Scotia Sea and partly from the Weddell Sea. It consisted almost entirely of stages v 

 and vi — stage v in the upper and stages v and vi in the lower nets. It is probably similar 



