APPENDIX K: KYLE __ 4 _ 



These two instances will perhaps suffice, to show the necessity of a critical res ate- 

 ment of the general ideas involved in the problem of overfishing, more especially as, 

 except for a few special purposes, the interpretation of the statistics, available at the 

 present time, depends more upon individual experience and breadth of view than upon 

 their own intrinsic worth. 



The aim of the present portion of this work is therefore twofold; firstly, to criticise 

 and arrange in their relative order of importance, the general ideas connected with the 

 problems of overfishing and decrease of fish; and secondly, to examine the existing 

 statistical data with regard to the principal species of foodflshes caught in the North Sea. 



In order to carry out this aim, it is advisable in the first place to go away from the 

 North Sea, and consider two less complicated regions, where the course of the fishing 

 throws considerable light on the problems concerned. The first example is taken from 

 the Norwegian fisheries, where the physical and biological conditions are so different from 

 those found elsewhere, that the effects of severe fishing stand out in marked contrast to 

 what has been observed in the North Sea. The second example chosen is that of the 

 Kattegat, where the conditions are more akin to those of the North Sea. In both cases 

 we have to deal with the plaice. 



A discussion of these will show the advisability of regarding overfishing (for the 

 time being), as a practical and economical problem, which has to be measured not in 

 terms of quantity but in terms of value, i. e. of the capital employed and the income 

 earned. Theoretically, it seems possible to measure overfishing by means of the quantities, 

 and if all the factors were known — the amount of the fishing power, the reproductive 

 fertifity, rate of growth and mortality of the species concerned and the total quantities 

 taken for man's use per annum — a good mathematician might be able to calculate the 

 precise point where overfishing begins. Practically, his calculation would be waste labour, 

 if the average price of fish rose or fell, in the meantime, by but a fraction of a penny. 



On the other hand, the decrease or increase of fish, either in numbers, quantity or 

 quality, is a special scienfific problem which can be solved if certain factors are known. 

 If the physical and biological conditions, surrounding a species on a given region, remain 

 practically the same over a period of years, and the amount of fishing to which it is 

 subjected is maintained practically at a maximum throughout, then for a species which 

 spawns once a year, the principal factor is the total quantity (by weight) taken per annum. 

 For practical and economic purposes, however, it is not sufficient to know that a species 

 is maintaining itself on an area so far as total weight is concerned. It is of more impor- 

 tance economically that the large fish, or rather, the fish which have the best market- 

 value, should not decrease. Even if the total weight has remained practically constant 

 over a period of years, the question has still to be considered, whether the size and quality 

 of the fish taken have likewise remained constant. For economic purposes, therefore, the 

 average size or weight of the fish taken has also to be considered. 



The available statistics of the plaice fisheries in Norway and the Kattegat will enable 

 these positions to be exemplified. The statistical data for the fisheries of the North Sea 

 are unfortunately more imperfect and complicated, so that the conclusions are more of 

 the nature of probabilities than certainties. The difficulties in the way will be pointed 

 out later. Meantime, it is of importance to mention the assumptions which are made, in 

 using statistical data for the solution of the question of decrease or increase of fish. It 



