DISTRIBUTION OF YOUNG STAGES OF EUPHAUSIA SUPERBA 131 



(5) Drake Strait 



(a) and {b) yielded no eggs or larvae (Fig. 49). 



{c) March 193 1 (Sts. 644-651). Fig. 50. 



This line of stations was made rather to the east of the Drake Strait from a point west of Elephant 

 Island towards Staten Island. Of seven stations at which vertical nets were fished four were south of 

 the Antarctic convergence and at all of these eggs and larvae were taken. 



At St. 644 a few eggs only were taken and at St. 646 eight Calyptopis i and 2, with the latter stage 

 predominating. 5200 larvae representing Metanauplius, Calyptopis i and 2 were taken at St. 647. 

 The Metanauplii, 4279 in number, were confined to the two lowest nets between 500 and 1000 m. 

 The Calyptopis were distributed throughout the six nets with greatest concentration in the surface 

 net. 



There were eighty Metanauplii and Calyptopis i at St. 648, with the Metanauplii predominating. 

 The conditions at this station have been mentioned above, p. 115. 



No E. stiperba were taken at the remaining stations north of the Antarctic convergence. 



(d) April 1930 (Sts. 378-388). Fig. 51. 



This line of stations was made immediately after the completion of the combined Discovery II- 

 William Scoresby line (4(e)), from the South Sandwich Islands to the Burdwood Bank. It will be 

 remembered that in that line Furcilia 5 predominated in the east and Furcilia 2 and 3 in the west. 

 Vertical nets were worked at eight stations in the present line. Four of the stations were south of the 

 Antarctic convergence and the remainder in warmer water. 



Larvae were taken at Sts. 378 and 383, the first and third stations of the line. There were few 

 larvae at the former, eleven in all, representing the three Calyptopis stages with the 2nd predomin- 

 ating. Larvae were once again abundant at St. 383, 787 being taken between 50 and 250 m. The three 

 Calyptopis stages and Furcilia were represented, with Calyptopis 3 predominating. 



The Drake Strait lines are chiefly important for the yield of the Metanauplius stage 

 which one of them presents. The regional occurrence of this larval stage has been men- 

 tioned previously (p. 1 14), and its preference for warmer water pointed out. At both lines 

 of stations from which we have records of larvae the greatest concentration is to the 

 northward rather than the southward, and in the warmer rather than the colder water. 

 These concentrations are of larvae having young stages predominant, in the one line 

 Metanauplius and in the other Calyptopis 3. 



Both lines were made late in the summer season, yet such early stages as Meta- 

 nauplius and Calyptopis i were still obtained, which shows that in this species, unless of 

 course development is delayed in some of the young larvae, the time range of spawning 

 is not restricted to a short, definite period. 



17-2 



