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the hatcheries must be regarded as quite without importance. Compare for example 

 what has been shown above on the catches of the "Poseidon" on the fishing ground 

 "Tampen". 



c. When the young bottom stages grow up many miles distant from the places 

 where the eggs and larval stages developed, any purely local result from the liberation of 

 the larvas cannot be expected, and 



d. when the existence of great variations in the drift of the larvae and in the quan- 

 titative occurrence of the year-groups up to several years old has been proved, all these 

 conditions and phenomena must possess dimensions which far exceed the limits of human, 

 practical endeavours. 



What has been said here applies to our observations in the open sea. It has however' 

 been maintained from many sides, that the conditions in smaller, more enclosed areas ot 

 the sea would render it possible to influence the stock within this. In Norway a great 

 deal of labour has been spent in the elucidation of this question and we may refer to 

 Knut Dahl's paper, which gives the results of the investigations instituted for this purpose. 



Dahl's investigations were intended to ascertain, especially in these small waters 

 (presumably the smallest fjords which could be found for the purpose), what quantities of 

 eggs and larvas occurred there under the natural conditions, in how far these plankton 

 stages were local, if they remained in the fjords and what fluctuations occurred in the 

 quantity of the younger bottom stages. 



These investigations had to contend with the difficulty that the localities investigated 

 lay, not beyond the boundaries of the spawning places of the cod but within these. As 

 mentioned above, it is in that case very difficult to determine with certainty, to what 

 extent movements of the larvae and young fishes take place. We saw there also, that 

 we possess the best and clearest evidence of the drift of the plankton stages from the 

 boundary regions. 



Dahl has now succeeded in discovering that a considerable spawning also takes 

 place in the small fjords, so that it was impossible to determine any increase whatso- 

 ever of the plankton stages after the liberation of about 30 million eggs and larvae. The 

 hydrographical conditions in the fjords showed further great changes, as could be 

 determined both by salinity observations and by direct current measurements. Outside the 

 fjords in the Skager Rak a very strong current was found flowing in a westerly direction, 

 which presumably also greatly influenced the movement of the water in the fjords. Fluc- 

 tuations in the plankton stages occurred parallel with the hydrographical changes observed; 

 a connection between the movements of the currents and those of the larvae is therefore 

 very probable. The young bottom stages also showed the characteristic of occurring in 

 very varying quantity in different years. It seems of special importance that the same 

 characteristic in the quantitative occurrence of the young littoral fish could be detected 

 each year everywhere in the localities investigated, and this both where the larvae had been 

 set out and also where none had ever been liberated. 



It has therefore not been possible even in these small localities to prove successfully 

 or even to make it appear probable, that the stock of fish might possibly be increased 



