THE SALT-WATER FISHEEIES OF BOHUSLAN. 195 



have been entirely cousigiied to oblivion. MacCullocli's opinion, however, 

 has met with great and universal favor, and has been shared by Yarrel^ 

 Parnell, and others, whilst Professor N'ilsso7i''s opinion is held by G. 8. 

 Sumlevall, El'strom, Valencienues, 3IitcJiell, Berthelot, and others. 



Kecent theories regarding the annual migrations and coast-visits of 

 the herrings chiefly differ from each other in this, that the migration is 

 thought to extend over a greater or less territory, just in proportion as 

 the lierring is considered a more littoral or more pelagian iish, and in as- 

 cribing various natural instincts as the causes of these migrations. 



42. We must finally mention the theory advanced in explanation of 

 the fisheries of new herrings on the western coast of Korway, that the 

 herrings do not, as is generally supposed, spawn every year, but only 

 every other year.^^ This theory was in the beginning only used in expla- 

 nation of the exceptional occurrence of a small number of so-called 

 '' herrings-of-i)assage," but was more generally applied when people be- 

 gan to take into consideration the unusual and frequent occurrence of 

 so-called " new herrings" or '' winter herrings." If this theory is correct, 

 the same herrings would, as a general rule, visit the same coast only 

 every other year for the purpose of spawning, and the annual fisheries 

 of spawning-herrings must, therefore, principally be caused by herrings 

 which alternate in their years of spawning. The frequent visits which 

 herrings pay to the coast between the spawning of every other year, but 

 during the spawning-season, must, therefore, be considered as exceptions 

 occurring at the end (or the beginning) of a period of fisheries (for spawn- 

 ers). After having spawned the spring-herrings would not occur among 

 the summer-herrings during the following summer and grow fat, which, 

 as we know, takes place quick enough, but would remain lean for more 

 than a year. Still less is there any cause why the so-called "new her- 

 rings" should api^ear so seldom during the fishing-season and so fre- 

 quently after its close. This'theory* may be convenient for exi^laining 

 the above-mentioned phenomena, but it cannot be fully accepted unless it 

 can be harmonized with other phenomena, which are the i)rincipal ones 

 to demand an explanation."^*^ The investigation of the subject only be- 

 comes more comi)licated through such theories, whose value is, therefore, 

 very doubtful. 



* 43. It has been mentioned before (22) that the young herrings begin 

 to wander about at an early age, chiefly to seek food or shelter from their 

 enemies, or i^ossibly more agreeable places of sojourn. It has frequently 



^ Althoiigli it is generally supposed that herrings can sjiawu several times in succes- 

 sion, we have no positive proof of this, and this question seems actually never to have 

 been examined scientifically. 



* The theory mentioned in the beginning of 42. — Translator's note. 



^1 do not mean to imply by this that every herring capable of propagating the spe- 

 cies must spawn every year, but merely that when possessed of full health and strength 

 every herring will generally do it. It must, moreover, be remembered that the indi- 

 vidual fish composing one and the same school do not all become capable of propagat- 

 ing the si^ecies at the same age. 



