352 DISCOVERY REPORTS 



flowing out of the Weddell Sea there was a population in stages iii and iv, and in water 

 flowing into the Weddell Sea as the East Wind Drift current, south of 66° S, there was 

 a population in stage v. One station (i 142) was taken in a tongue of water flowing south- 

 wards from the South Atlantic. Here the Rhincalanus population was in stage iv. It is 

 presumed that the stock at this station and at those on this line taken in water flowing 

 out of the Weddell Sea owes its origin to the South Atlantic deep water (p. 349). 



8. It would appear that in the season 1932-3 spawning began in the warmer Antarctic 

 water near the convergence perhaps at the beginning of December near South Georgia, 

 but possibly earlier than this farther west in the Drake Passage, and later spread south- 

 wards into the Scotia Sea. It is thus possible to state that there must be a movement 

 southwards of the spawning area from the convergence into colder Antarctic water as 

 the summer advances (pp. 345-8). 



COMPARISON OF SEASONS 1931-2 AND 1932-3, FALKLAND SECTOR 



In the first half of both seasons, 193 1-2 and 1932-3, the area of maximum abundance 

 of Rhincalanus gigas lay in the Drake Passage, Western Scotia Sea and South Atlantic, 

 and the area of greatest scarcity in the Weddell Sea and in water of Weddell Sea origin. 

 In the first half of 193 1-2 the region of greatest abundance, in which more than 10,000 

 individuals were taken at all stations, occupied Antarctic water of Bellingshausen Sea 

 origin over a wide area in the Falkland Sector from the western Drake Passage to the 

 South Atlantic. In the early part of the second season, 1932-3, however, this region was 

 restricted to a comparatively small area between South Georgia and the Falkland 

 Islands. This was perhaps in part due to the fact that the waters of the Drake Passage 

 were investigated nearly a month earlier than in the previous season, so that the main 

 mass of the population was still out of range of the nets. Between the Falklands and 

 South Georgia in February much the same conditions were found in both seasons. The 

 catches were fairly large on the Antarctic side of the convergence but smaller than they 

 were in this area earlier in the year, in November and December. On the sub-Antarctic 

 side of the convergence a very marked reduction in the catches was found during 

 February in both seasons. This may either be due to the fact that the winter descent 

 from the surface strata takes place earlier north of the convergence in sub-Antarctic 

 water than south of it in Antarctic water, or, more probably, to the reduction of the 

 summer spawning in the sub-Antarctic so that the over-wintered generation in those 

 waters dies out after mid-summer and is replaced by a greatly diminished summer 

 generation. 



In 193 1-2, in the Bellingshausen Sea current, the ascent from the winter level to the 

 surface apparently took place more irregularly and over a longer period than in 1932-3. 

 During the latter season the majority of the catches appeared in the upper nets from the 

 beginning of November onwards until February. In 193 1-2, however, the figures sug- 

 gest that the ascent to the surface began near the convergence in November, but that at 

 stations away from the convergence it did not appear to have taken place until the 

 middle of December. In water of Weddell Sea origin in both seasons the catches were 



