242 



DISCOVERY REPORTS 



The monthly numbers of resting whales in the small material available from the work 

 done in 1932-3 are shown graphically (Fig. 7) together with results from the 1934-5 

 material from two factory ships which started whaling in October (the rest started at the 

 beginning of December). The 1934-5 material for these two ships is tabulated below 

 to show the numbers and percentages of pregnant and resting whales in the monthly 

 catch, as shown by the ovaries: 



It will be seen in Fig. 7 that the percentage of resting whales in the material above at 

 the beginning of the season is 25, declining to 22 in November. There appears to be no 

 significant change in the proportions of resting whales in the catch in October and 

 November, but from November onwards to the end of the whaling season there is a 

 steady increase. (The figures for April are too small to be included in the graph.) 



On the same figure is shown the percentage of resting whales from the 1932-3 data, 

 calculated solely in terms of pregnant and resting whales and excluding the lactating, 

 so as to bring the material into line with the 1934-5 computations and all available 

 South Georgia data treated in the same manner. The same general feature is 

 observed. 



A suggested explanation of the curve is as follows. The resting whales which are 

 present at the beginning of the season and in November are probably whales which 

 have stayed south all winter, such as Hart found. Their numbers are later supplemented 

 by those whales which have finished lactating and join the resting class. As the season 

 progresses more and more will have finished with lactation and become resting. 



The ovary collections for two subsequent seasons gave results as shown in the table 

 on p. 243. The number of non-pregnant whales is considerable in both years, but 

 there is some disagreement between the percentages. For the sake of the argument 

 that follows the two may be taken together to give an average of 58 per cent pregnant. 



