210 DISCOVERY REPORTS 



found by King & Demond (1953) in the Central Pacific where shallow night hauls gave consistently 

 larger volumes than the day ones. In this respect it is interesting to note that the variations due to 

 time of day did not mask the major variations, which were latitudinal. 



Table 3. The monthly variation in the mean concentration (i.e. volume per 50 m. of haul) at six depth 

 intervals in the sub-Antarctic and Antarctic. Numbers of observations are given in brackets 



SUB-ANTARCTIC 



m is 



u m 1 



rrr 



ANTARCTIC 



MONTH 



i nmivvinimvinixxximi 



rrrni.imrrf 



Fig. 7. Monthly mean vertical distribution of the standing crop in the sub-Antarctic and Antarctic. The number 

 of observations and the mean concentration of plankton at each depth are given in Table 3. 



Fig. 7 illustrates very clearly the seasonal variations that occur in the vertical distribution of the 

 standing crop of plankton. In the winter months of July and August, and the early spring month of 

 September, the bulk of the plankton is concentrated below 250 m., particularly in the Antarctic zone. 



