PHOSPHATE, PLANKTON AND WHALE DISTRIBUTIONS 



295 



sX 



\K ^3 5 2"2>>_ 



56/3 2 5 5_ 



tll_2 (i4/44 4 



FIN WHALES 



BLUE WHALE5 



P 2 05M6M.PM 3 



no- 



Fig. 159. Whale distribution in November 1930 (from Kemp and Bennett, 1932). 



Blue whales at the same time. We see that the majority of whales of both species were 

 taken in the region of high phosphate content and low pH values to the north-east, 

 whilst we also see an interesting lesser concentration of Fin whales coinciding with the 

 small patch of higher phosphate content to the north. No whales however were taken, 

 as might have been expected, in the region of higher phosphate and lower pU values to 

 the north-west. The major importance of these correlations is that whales are not found 

 in any numbers in regions of low phosphate content. 



Turning now to the South Shetlands survey of February 1929, the only one for which 

 phosphate values together with whaling figures are as yet available, the phosphate con- 

 tent is plotted in Fig. 161 . The phos- 

 phate values in these latitudes farther 

 south are much greater even than 

 those at South Georgia, but here 

 also are areas of higher and lower 

 phosphate value. We see an area 

 of very high phosphate content close 

 against the Weddell Sea, where pre- 

 sumably very little phytoplankton 

 production has taken place, and an 

 area of comparatively low phosphate 

 content where presumably there has 

 been a heavy production. The pH 

 values are plotted in Fig. 162 where 

 the area of higher />H values, i.e. 

 those of 7-95 and over, is seen to 



100 



90 



80 



70 



60 



O 

 O 



iS 



o 



o 



o 



! CDC 



CD 



812 14 16 



•IB B 20 ' 22 ' 24 ' 26 ' 



■28 830 -32 834 PR 



Fig. 160. Correlations of phosphate and pH values, each 

 averaged for the top 50 m., at stations in the November 



correspond roughly with the area 1930 survey. 



38.2 



