THE SALT-WATER FISHERIES OF BOHUSLAN. 181 



from the ocean, are never visited by any of the great schools of herrings, 

 and, therefore, offer no opportunity for any really "great" herring-fish- 

 eries. To this circumstance Bohusltin doubtless owes, to some degree at 

 least, the comparatively short duration of its fishery periods, and the 

 long intervals between these periods. In addition to this, it must not 

 be forgotten that the coast of BohuslJin is not near as much laved by 

 northern waters containing mucli "herring-food" as the coasts of the 

 I^Torth Sea. 



31. Itegarding the influence on the herring of Mologiml causes, it will 

 be clear that, in one respect at least, viz, the satisfying of the herrings' 

 demand for food, they exercise a very decided influence, and also that 

 they entirely depend on climatical, hydrological, orographical, and geog- 

 nostical conditions. From the foregoing it will be clear that the "her- 

 ring-food," both by its quantity and by the depth in which it is found, 

 will have an influence not only on the herrings but also on the herring- 

 fisheries. Although the herring's certainly do not take any food whilst 

 spawning, the occurrence of "herring-food" has, nevertheless, also an 

 influence on the spawning herrings' course near the coast ; since they 

 still need a little food, and all the more, the longer before the commence- 

 ment of the spawning-season, they come near the coast. It is self-evi- 

 dent that the quantity of "herring-food" in certain coast- waters will de- 

 termine the size of the herrings living in these waters ; and even the 

 greater schools of herrings living in the open sea seem to a great extent 

 to be dependent — at least as far as their young ones are concerned — on 

 the quantity of food found near the spawning-places. As the quantity 

 and occurrence of " herring-food " are dependent partly on the above-men- 

 tioned i)hysical conditions and partly on the quantity of food and of organic 

 matter necessary for its formation,''^ it will easily be understood how im- 

 l>ortant it will be to obtain an accurate scientific knowledge on this sub- 

 ject, based on the horizontal and vertical distribution of the "hening- 

 food," with a special view to its dependence on physical conditions; and 

 as the acquiring of such a knowledge involves much trouble and time, 

 very little has so far been done in this direction, so that our knowledge 



■*^See: K. Moebius, Das Thiefleben am Boden der Deidschen Ost- tmd Nordsee, Berlin, 

 1871, p. 9, and: Die Auster und die Ausiei-n ivirihschaft, Berlin, 1877, p. 83, in which last- 

 mentioned jilace he says : "Every cenobitic region possesses in every period of gene- 

 ration the highest degree of life which it is capable of forming and sustaining. All 

 the organic matter contained in such a region is, therefore, completely absorbed by the 

 beings produced there. It is probable, therefore, that in no part of the earth capable 

 of producing life any organic matter is left for spontaneous generation." But is it not 

 possible that exceptional conditions in one place may destroy a species which, also, 

 without limiting the other species belonging to this cenobitic region, could exist there? 

 And might there not bo places where a species might flourish and live in large num- 

 bers, no matter whether it was formed there or brought there from other places, but 

 where, owing to the want of the conditions necessary for utilizing the organic matter 

 found there, such matter is stored up for the future ? And does not geology furnish 

 many similar instances ? And do not the Polar regions owe th?ir extraordinary wcaltli 

 of organic matter to some such process of storing up during milder climatic conditions? 



