HEHRINCi. 



965 



are nearly 400 fathoms of water. The continuation of j thiit it can descend to considerable depths, of sorae 

 the channel, up to tiie 40-fathonis line, follows the i hundred fathoms at least, though pi-obably not to the 

 west coast of iSweden south to about the latitude of 1 deepest parts of the Atlantic. 



Kon"'sbaci<a, i. e. as far as the true coast lisliery for 

 Great llerrinu- has ever extended to the south in 

 Sweden. 



To trace the Herring to its ocean liome is a hope- 

 less task. Conjecture must still play a prominent part 

 in all opinions of its life in the depths. ISut s(j much 

 is apparently clear, that its ^\■anderings follow tlic de- 

 pressions and sfeejis of tiie Ijottom. How deep it can 

 descend, we i<now not; but the advanced development 



As Mac Cullocu has remarked, the ro\ings of 

 the Herring have three motive causes, the quest of a 

 si)awning-place, the chase of food, and the dread of 

 its pursuing enemies. 



The spawning-season of the Herring lasts all tlie 

 year round; Init only a part of the wandering multi- 

 tudes, in general tliose of tlie same age, are in l)rced- 

 ing condition at the same time. Different spawning- 

 seasons may hence characterize different localities, and 



Fig. 241. Tlie Xorth-eastern Atlnnlic togetl.c-r with the North Sea and tlie Baltic. After 0. Torell. 



of the adipose membrane covering the head ranges it 

 nearer than the Mackerel to the true deep-sea fishes. 

 The pressure need not greatly distress the Herring, for 

 only few fishes can so easily adapt tlie distension of 

 the air-bladder to varying degrees of pressure. The 

 lower temperature of the depths need not deter it, for 

 fishes with so extensive a geographical range must by 

 nature be accustomed to wideh' different temperatures, 

 tlioiigh the Herring seems sensitive to sudden varia- 

 tions. The same may be said of the greater or less 

 salinity of different layers of \vater. All that we know 

 of the Herring's nature well admits of the assumption 



in the same locality it is not uncommon to find two 

 separate spawnings every year. In the Atlantic the 

 two spawnings, where they occur, take place before and 

 after the winter, in the Baltic before and after the 

 summer. This a])plies to the main l)ody of the shoals: 

 but during the intervening periods isolated instances of 

 breeding fish may be observed almost everywhere. As 

 a rule the oldest Herrings spa^vn first, in the autumn, 

 the younger ones later, when the spring has set in or 

 in the summer. From the Gulf of Bothnia Gisler ad- 

 duces the Sprin;) or Ice Stromming, -which spawns within 

 the island-belt when the ice breaks up, the Xet Strom- 



