ADMINISTRATION-REPORT 1902-03 — XXXVI — 



In addition to the regions of work in tlie North Sea being mariîed off for 

 each nation, these investigations have led to the fixing of many things in regard 

 to method, measurements etc. For the extremely important questions centred 

 round the migrations of the herring, the first things to be determined are how far 

 the herring shoals vary their habitat at different periods of the year, and how far 

 they can be followed seawards from the Shetland coast on the one hand and 

 from the Norwegian coast on the other ; also in the second place, whether there is 

 any mingling of the two shoals in the centre. Special experiments are to be made 

 for this purpose on the 'boundaries of the herring fishery regions, and with the 

 assistance of the statistics a picture should be constructed of the distribution of the 

 herring shoals within the region under observation. 



Investigations Examination of the extraordinarily important question of over-fishing can 



the"q"estior'of scarccly be attempted without the assistance of statistics. It seemed advisable 

 Over-fishing however, that each nation should in the first place collect the statistical data for 

 itself in the form best suited to its requirements; agreement might be reached 

 later as to the special form in which all the data could be brought together. Other 

 investigations and methods of research could be undertaken forthwith; on the one 

 hand, were those for which the international cooperation Avas in eminent degree 

 desirable, such as the more exact determination of the grounds frequented in 

 quantities by the undersized fish, and the determination of the rate of growth and 

 migrations of certain species of fish at different periods of the year, by means of 

 marking and returning to the sea large quantities of these species. On the other 

 hand, there were special researches for which a division of labour was possible 

 so that the material collected by several states could be sent to special workers 

 in various countries. Such researches are, the question of the formation of races 

 and varieties, the reproductive fertihty of fishes and so on. 



The cooperative work (Appendix C) has been commenced energetically in the 

 first year by the majority of the participating states, and with regard to all the 

 investigations. Thanks to the cooperation, (1) fishery experiments have been set 

 on foot which have for aim the determination of the condition and wealth of the 

 fishing grounds; these experiments are carried on at the same time at different 

 portions of the region under survey, over a greater range therefore than any 

 hitherto ; (2) the marking of fishes of different species and of various sizes, and re- 

 - turning them again to the sea, takes place in such a systematic manner and to 

 such an extent that very important information with regard to the movements and 

 increase in growth of fishes will assuredly be obtained; (3) statistical data is being 



