SOME EFFECTS OF WHALING ON THE SOUTHERN STOCKS 

 OF BALEEN WHALES 



R. M. Laws 



National Institute of Oceanography, Worniley 



Modern whaling is mainly based on the value of whale oil and for profit 

 depends on large catches. It dates from 1904 when Antarctic rorquals 

 (Balaenopteridae) were first exploited at South Georgia. Up to 191 3 the 

 industry was based on the humpback whale, Megaptera novaeangliae 

 (Borowski), which was quickly depleted in the South Atlantic sector. The 

 blue whale, Balaenoptera muscuhis (L.), then supported the industry and with 

 the development of pelagic whaling in the late 1920's the area of the whaling 

 grounds expanded to become almost circumpolar. Antarctic pelagic whaling 

 now accounts for three-quarters of the world catch of baleen whales. 



The decline of the blue whale in the southern hemisphere began about 

 193 1 and increasing numbers of fm whales, Balaenoptera physalus (L.), 

 appeared in the catches. This is currently the most important species and 

 constitutes some four-fifths of both the world catch and antarctic catch of 

 baleen whales. 



This paper is therefore concerned mainly with the fm whale and with 

 antarctic pelagic whaling during the last three decades. 



In this time there have been two main periods of intensive pelagic whaling 

 divided by the war years 1939-45, when the catches fell to a very low level. 

 For convenience I shall refer to the two main whaling periods as the pre-war 

 and post-war seasons. 



SAMPLING PROBLEMS 



There are certain basic difficulties which are not met in other groups of 

 exploited animals, namely, the very wide geographical distribution, the 

 large size of the animals and the prohibitive cost of an adequate research 

 programme. These and other problems affect the interpretation and elucida- 

 tion of changes in the composition of whale populations and I think it 

 necessary to summarize and discuss them here. 



