EFFECTS OF WHALING ON BALEEN WHALES 



US 



1958-9. It seems clear that the fin whale stocks in area III are in the best 

 condition relative to the other areas, and may possibly be holding their own 

 at the present rate of exploitation. 



January 

 catch 



1955/56 1956/57 1957/58 

 Seasons 



1958/59 



Fig, 3. — Comparison of fin whales per C.D.W. for January and for the full season 

 with the intensity of catching. 



It might still be objected that the influence of catches of other species, 

 though small, has been responsible for the stabilization or decline in the fin 

 whale values. Is it possible to eliminate the effect of the catches of other 

 species ? This uncertainty can be removed if we compare the January values 

 for fin whales per C.D.W. from the 1955-6 season onwards. In these years 

 only two blue or humpback whales were taken annually in January and 

 negligible numbers of sei whales (average 1955-6 to 1957-8 only forty-seven, 

 or some 0-4 per cent of the fm whale catches). Relatively small numbers of 

 sperm whales were taken; they do not amount to more than 6-8 per cent 

 of the fin whale catches. In Fig. 3 the values of fin whales per C.D.W. for 

 January are compared with those fpr the total catches and with relative 

 catcher efficiency. In this four-year period although the average catcher 

 horse-power has increased by nearly 23 per cent the trend of the January 

 values of fm whales per C.D.W. is stable or decreasing. Competition between 

 catchers was less in the three later seasons. At the same time the percentage 

 of 'immature' whales in the catch (based on body lengths) has increased by 

 some 5 per cent (Fig. 4). 



In spite of the many complicating factors two inescapable conclusions 



