[5 J THE HERRING FISHERIES OF SWEDEN. 733 



general rule lias been treated far too lightly. If it is desired that this 

 question should be answered in a more satisfactory manner than it has 

 been thus far (which is amply sufficient as far as the aim of my investi- 

 gations is concerned), a person should be commissioned to make observa- 

 tions, who can give his whole time and undivided attention to the sub- 

 ject. 



The spawning-places which are the immediate occasion of the great 

 Bohuslan herring fisheries during the intervals when the herring do 

 not enter the eastern Skagerack, and during the herring periods when 

 they do not spawn near the coast, are not known j and owing to lack of 

 time and means I have not been able to make a search for them, although 

 from information furnished by fishermen and from other circumstances 

 known to me, I have been enabled to form a tolerably correct idea as to 

 t?heir location. It is certain, however, that Mr. von Yhlen's and Profes- 

 sor Smitt's supposition that the herring spawn in the open sea, off the 

 coast of Bohuslan, in the great depths, and on the soft clay bottom which 

 is found there, is incorrect; for nothing of the kind is known from any 

 other sea; but, on the contrary, wherever the spawning of the herring 

 has been observed it invariably was found to take place on a hard bot- 

 tom, or on one covered with rich vegetation. It should be remem- 

 bered that the spawn of the herring adheres to the object over which 

 the spawning process goes on, and that therefore the clay bottom of the 

 great depths cannot be a suitable place. 



Another question of great importance relative to the object I had in 

 view was the one as to the cause of the close of the last Bohuslan her- 

 ring period, and of its return. With the view to explain this periodicity 

 from physical or biological circumstances, I have endeavored to ascer- 

 tain, as accurately as possible, the influence of these circumstances on 

 the movements of the herring, and have at the same time studied 

 as carefully as possible all the historical data relative to "the different 

 herring periods and the great herring fisheries in the Korth Sea. I 

 have done this in order to find out whether a secular periodicity was 

 a general characteristic of these fisheries, and whether this very perio- 

 dicity formed a sort of connecting link between the different fisheries. 

 My observations have finally led me to the conclusion that the great 

 Bohuslan herring fisheries for nine centuries have formed a regular 

 series of periods, which, in spite of what Axel Boeck thinks he has 

 proved, alternated with the great spring herring jjeriods on the west 

 coast of Norway; and that, owing to the great depth of the sea and the 

 lack of great connected banks, suitable for spa-wning place%-^ the 

 coasts of Norway and Bohuslan, the coast fisheries in these regions could 

 not be carried on with seines at all times with the same favorable re- 

 sults. On the other hand, near the coasts of Great Britain there is found 

 as extensive plateau of such banks, whose location is su€h th,at the 

 fishermen can reach the herring when they move towards these banks, 

 or when they occupy them, without being obliged to go away from the 



