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of fish. These statistical data were however affected by great shortcomings. They were 

 inexact, for example, in regard to the determination of the species; whiting and small 

 haddock were grouped together. Further, the returns were arranged without regard for 

 the fishing places according to the coast on which the fish were landed; thus, even the 

 cod and haddock from Iceland, the Faeroes and the North Sea were included together 

 under one harbour. It is evident, that data of this kind can give no information on the 

 influence of the fishery in one definite region, e. g. the North Sea. All fluctuations in 

 the statistics could just as well be explained as resulting from a change of grounds by 

 the fishing fleet as from any alteration in the stock of fish. It has therefore been a very 

 valuable result of the fisheries investigations of recent years, that it was possible to state 

 clearly and definitely the requirements which the statistical data must fulfil, in order to 

 be able to give a satisfactory picture of the stock of fish. At the present time the fol- 

 lowing information is asked for in the fisheries statistics of various countries: 



1. Time of fishing (date, number of hours fishing). 



2. Fishing place. 



3. Precise distinction of the species. 



4. Distinction according to size (commercial classes). 



5. The data are to be given in terms of weight. 



A still more exact method is used on board the research steamers in the study of 

 the stock of fish, the number, length and age of the fish taken being also investigated. 



In this way it has been possible, not merely to arrange the fish into classes accord- 

 ing to size, but also to compare the relative abundance of the different year-groups 

 with one another. This comparison has led to such important results, that it must be 

 considered as an absolutely necessary task of the future representative 

 statistics to include number, measurements of length and determinations 

 of age in the data collected. It has proved, namely, that the commercial classes 

 contain several year-groups, and it was thus impossible to demonstrate any regularity 

 whatsoever in the changes or fluctuation of these classes from year to year. It is quite 

 different with the year-groups. As we have seen above, the study of these could lead 

 to a true insight into the question of the relation of the fisheries to the stock of fish. 



The result yielded by the study of the natural history of the haddock and the 

 cod seems to be this, that certain fluctuations in the quantitative occur- 

 rence of the younger year-groups are so large, that they do not arise from 

 the fisheries. This by no means implies, however, that the fisheries cannot exert a 

 very great influence on the younger year -groups after they have once reached the 

 bottom stage. Even if in any one year — quite independent of man's in- 

 fluence — a new stock of haddock were to appear in the North Sea, the 

 question would still remain, how can the fisheries make the best use of 

 this stock. In other words, it is allowable to think, that the fishermen, in taking the young 

 haddock before these have reached any mentionable value, are treating the annual natural 

 increase in an uneconomical manner. We saw for example, in the section on the had- 

 dock, that the class "unmarketable" taken by the trawlers and then thrown overboard in 

 the dead condition, is not quite inconsiderable in numbers in proportion to 



