DISTRIBUTION OF YOUNG STAGES OF EUPHAUSIA SUPERB A 



163 



GENERAL REMARKS ON DISTRIBUTION 



Notwithstanding the fact that the records of the occurrence of eggs indicate that 

 E. superba prefers the far south for spawning, the place where eggs were taken differs 

 widely from those where Metanauplii and Calyptopis i were taken. It is felt that con- 

 centrations of eggs, which were found in the Bransfield Strait, almost to the exclusion 

 of other localities, must be due to the peculiar hydrographic and bathymetric in that 

 region. The distribution of Metanauplius and Calyptopis i (Figs. 32, 76) indicates that 

 these forms have no immediate relation to the occurrence of pack-ice nor are they re- 

 stricted to the southern parts of the Antarctic. In the west of the Scotia Sea Meta- 

 nauplii extend to the north almost to the Antarctic convergence. To the east, westward 



Fig. 76. Distribution of Euphausia superba, ist Calyptopis. 



of South Georgia, at St. WS 197 where 1 1 5 were taken, they are found at a time of year, 

 the second half of April, when ice is far to the southward. Similarly Calyptopis i is so 

 scattered in its distribution that no correlation with pack-ice can be obtained. The time 

 between the laying of eggs and their development into Calyptopis i is assumed to be 

 comparatively short, so that the distribution of stages up to this point should be ap- 

 proximately the same as that of the spawning aduhs. When the larva reaches Calyptopis 

 I the vertical migration already noted in this and subsequent stages will affect the 

 regional distribution. 



If spawning took place at the surface in proximity to ice we would expect to find that 

 increasing advancement of development in the larvae would be correlated with in- 

 creasing distance from the regions where pack-ice is abundant, but nothing of this 

 nature is shown in the material examined. Investigation of the adults and the occur- 



