258 



JOHAN T. RUUD 



In the history of whaling there is ample evidence that whale stocks are easily over- 

 fished and depleted, if not to extinction, at least to such a degree that whaling is 

 rendered unprofitable. It is only natural, therefore, that we, who have witnessed 

 the gigantic expansion of modern pelagic whaling operations in the Antarctic, are 

 on the alert for signs of over-fishing of the stocks of blue and fin whales. Such signs 

 are now evident: (1) increasing numbers of small and sexually immature whales in 

 the catches which result in a decrease in the mean length, indicate a corresponding 

 decrease in the average age and (2) decreasing catches per unit of effort threaten the 



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economy of the industry. This trend is influenced to some extent by the changes in 

 the varying regulations imposed on the industry. Hence, although the trend seems 

 to be unmistakable, the extent of the depletion may well be disputed. 



It is agreed that carefully planned and extensive marking experiments may produce 

 conclusive evidence of over-fishing, because the rates of fishing can be estimated 

 from the rates of recovered marks. However, extensive whale marking is costly 

 and there are great losses in the recoveries. Many marks are probably shed before 

 recapture, and marks are easily overlooked when the whales are worked up. It would 

 be better therefore, if the age composition of the catches were known, because, as 



