DISTRIBUTION OF YOUNG STAGES OF EUPHAUSIA SUPERBA 



(2) South Georgia surveys 



(a) Survey of August-September-October 1928 (Sts. WS 257-296). Fig. 40. 



As shown in Fig. 40 krill was present at several stations in this survey. All the larvae belonged to 

 the previous year class and with the exception of one adolescent at St. WS 282 and WS 295 all were 

 in the Furcilia 6 stage. The number of larvae recorded is remarkably small, never more than three at 

 any one station. 



(b) Survey of November-December 1930 (Sts. 475-525). Fig. 41. 



With the exception of one Calyptopis 3 at St. 477 all the young krill from this survey belonged to 

 the previous year class and were either Furcilia 6 or small adolescents. As in the previous survey the 

 number of larvae recorded is very small except at the innermost station near Bird Island where 169 

 were found. The i-m. net hauls, however, give a better indication of the abundance of the later and 

 larger developmental forms. The majority of the records are confined to the two uppermost nets, but 

 it is interesting to note that there are two from 1000-750 m. net hauls. The larvae do not show any 

 indication of restriction to the areas beyond the shallow coastal water, and the largest number taken 

 was close inshore. It is likely that this distribution is intimately bound up with the presence of pack- 

 ice in the vicinity of South Georgia during this survey and just before it was made. The predilection 

 of adolescents for the vicinity of pack-ice will be demonstrated later; it is mentioned here to give a 

 possible explanation of larvae so close inshore. 



(c) Survey of December-January 1928-9 (Sts. WS 321-365). Fig. 42. 



No larvae were caught during this survey. The only evidence of the presence of E. superba was one 

 egg taken at St. WS 323, the first deep-water station near Bird Island. 



{d) Survey of January-February 1930 (Sts. 300-358). Fig. 43. 



The stations at which larvae were obtained are shown in Fig. 43. To demonstrate that practically 

 all the larvae were taken at stations made in deep water the 250-m. contour has been inserted in the 

 map. 



The larval stages found were Calyptopis i, 2 and 3 and Furcilia i, 2 and 3, with Calyptopis 3 pre- 

 dominating. At one station (St. 356) gravid females were taken in the 250-100 m. net, but neither 

 eggs nor stages younger than Calyptopis 2 were found in the plankton samples. 



The larvae were fairly abundant in number with the maximum at St. 303, where 133 were taken. 

 Ninety-nine were taken at St. 320, four other stations had more than twenty larvae, and eighteen 

 stations had less than ten. 



At one station or another where the young euphausians were taken the net hauls from surface down 

 to 1000 m. yielded larvae, and although the 500-250 m. net appears to be the deep limit for the 

 majority it is not so for all of them. There is no reason to suppose that the larvae from the deeper nets 

 were dead specimens sinking to the sea-bottom, as it is easy to distinguish dead E. superba in the 

 samples. 



The occurrence of the larvae at stations made in water deeper than 250 m., as opposed to shallower 

 water stations, may be connected with their vertical distribution. It has already been remarked 



D .XIV 16 



