i62 Age jonsgArd 



more profitable whaling fields, the whale catchers have been considerably- 

 improved, both as regards size and equipment. Furthermore, the whalers 

 co-operate to a much greater extent than they did before. The increased 

 catches in recent years can thus be explained. During the season 1959, 

 however, the total catch decreased considerably, especially in the Lofoten 

 area, where the catch was 524 whales only. We have to look back to the 1940 

 season, ruined by hostilities, to find a poorer result in this area. 



CHANGES IN THE NUMBER OF CALVES IN THE CATCHES 



Since young animals are not protected by size limits and calves are taken 

 indiscriminately, our material allows a closer study of calves. Our growth 

 studies have shown that at least all animals which are up to 17 ft in length 

 are calves in the O-group. 



Fig. 3 shows the total number taken of calves in size groups 15 ft and less, 

 16 ft and less, and 17 ft and less in the Lofoten area and in all other areas. 

 Despite the increasing number of whales caught during the period from 1938 

 to 1958 smaller calves have become more and more scarce in the catches 

 since and including the season 1949. During the seasons 1941-8 the average 

 catch per season was about 300 animals 15 ft and less in length, as compared 

 to about 100 such animals today. 



As mentioned before, the total number of whales taken annually in the 

 Lofoten area has shown no decrease during the period from 1941 to 1958, 

 but the number of animals 15 ft or less in length decreased from about 200 

 animals per season during the period 1941-8, to about 50 in recent years. 



This decrease in the number of smaller calves may be explained by the 

 following alternatives : 



1. The bulk of the calves may be born earlier than previously 



Such a result would be expected if a selective catch of pregnant females 

 exploits the late breeders more heavily than the early breeders. We believe 

 that the effect, if any, of the regulations enforced in recent years is to the 

 contrary, because the closure of the Arctic waters to whaling after 30th June 

 will tend to protect the late immigrants more than those arriving early. 



2. The growth rate of calves has increased 



It has been observed for several species of mammals that improved conditions 

 of nutrition have resulted in an increasing rate of growth. Such an effect may 

 be expected, therefore, if the stock of minke whales has been much reduced. 

 On the other hand, the diet of the minke whale is very comprehensive, and 



