202 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



Even on the west coast of Norway it had (according to Loherg) been 

 observed diu'ing those spring-herring fisheries which had been going on 

 there since the close of the Bohusliin herring-fisheries in 1808, that the 

 herrings changed the places of their annual visits, and many attempts 

 were made to explain this phenomenon. None of these attempts, how- 

 ever, found much favor, and Loherg therefore maintained that probably 

 these changes were caused by the influence of wind and current. 



New interest began to be taken in this question when Axel BoecJc 

 proved that these changes were to some extent regular, and had been 

 shown to be regular not only during the older fisheries, concerning 

 which our sources of information were very meagre, and during the last 

 Norwegian spring-herring fisheries, but also dimng the great Bohuslau 

 herring-fisheries of the sixteenth and eighteenth centuries.'" 



Boech has not assigned any natural cause for this regularity in the 

 changes of the herrings' visits, and I believe that I am the first who has 

 made any attempt to find the causes of this phenomenon. I supposed 

 that during that part of the fishing-period when the herrings came to 

 the coast for the piu"pose of spawning, they preferred its northern por- 

 tion, because the temperature of the water was higher and more even 

 during the later part of the season when they came there, whilst the south- 

 ern coast would again offer peculiar advantages of temperature during the 

 earlier part of the season when they came there. DiiriDg that part of 

 the fishing-period, however, when the herrings came to the coast for 

 other purposes than spawning, their choice of a place would chiefly de- 

 pend on current and wind ; fishing on the central and northern coasts 

 was therefore more certain than on the southern coast. More will be 

 said farther on (60, 63) concerning these attempts to exj^lain the changes 

 in the migration of the herrings. 



50. Among the peculiar phenomena of the latter part of the last great 

 Bohuslan fisheries, attention has been drawn to the unusual occurrence 

 of small herrings among the larger ones during the last thirty years. 

 This i^henomenon has also become more significant since Axel Boeck has 

 shown that something very similar took place prior to the close of the 

 last Norwegian spring-herring fisheries, thus seemingly being an indi- 

 cation that the fisheries are approaching their end. During the above- 

 mentioned herring-fisheries none but large herrings were caught, and on 

 the coast of Bohuslan, for example, it was only immediately before and 

 after the annual fisheries that small herrings were caught among them. 

 The Norwegian spring-herring fisheries generally begin every year with 

 straggling herrings and are mostly followed by smaller herrings. 



The case which Boeck mentions from the Stavanger coast and from 

 the year 1766 does evidently not belong here, as it only proves a less 

 productive local autumn-herring fishery, when herrings of different size 

 are generally caught. 



'0 It is highly probable that the same was the case during the Bohuslan fisheries of 

 the second half of the sixteenth century, as the fisheries came to an end much earlier 

 in the southern than in the other parts of the coast. 



