HERRING AS AN ARTICLE OF TRADE. 187 



of small crustaceous animals, invisible to the naked eye, which are found 

 iu enormous quantities in the sea, both in shallow and deep waters. In 

 passiug sea-water through a straining-cloth, great numbers of these 

 small animals will be found. Their quantity, however, varies at differ- 

 ent seasons, during a changeof temperature, and at different depths. This 

 might possibly explain, to some extent, the appearance of herring at dif- 

 ferent depths. In summer these crustaceous animals are found nearer 

 the surface of the water, and at this season the herring is also found to 

 swim comparatively higher. Like other fish, the herring abstains from 

 food some time before and after spawning, and its stomach is therefore 

 generally found to be empty at this time. But after spawning it begins 

 to eat again, and gradually regains the strength and fatness which it 

 seems to lose during that process. This explains the fact that at some 

 seasons of the year the herring is leaner than at others. 



About two mouths before spawning, the herring may generally bo 

 considered the fattest and best. This fatness continues until spawning 

 is over, when the fish becomes lean and thin, and not fit to be caught. 

 The herring, after spawning, usually migrates to the deep sea to seek 

 food, and does not return till it has again gained in flesh and strength. 

 That the herring, like other kinds of fish, as soon as the spawning-time 

 approaches, again seeks the spot where it was born, is proved by the 

 circumstance, mentioned above, that certain easily recognizable tribes 

 or kinds of herring spawn every year at a certain time and at the same 

 place. That during one year it appears in larger numbers in one place 

 than during another, has doubtless its cause in the change of tempera- 

 ture, currents of the sea, and similar influences, which may even occa- 

 sion the entire absence of the herring from certain bays in some years. 

 Cold and inclement weather, during spawning-time, often destroys almost 

 the whole breed of one year, so that, naturally, for some years to come, 

 the kind of herring, in places where this has happened, will be very 

 poor. These, and other causes on which the development of herring 

 is dependent, are, however, as yet so little understood that nothing 

 definite can be said about them. But, on the other hand, it is well 

 known that man himself can destroy the herring in a bay of the sea 

 by catching the whole tribe, both old and young, in large nets, thereby 

 also destroying the spawning-places. 



It has already been stated that certain kinds of herring, particularly 

 the larger ones, spawn nearer the land, on a bottom overgrown with 

 sea-weeds. If this bottom is made unfit for spawning, by taking up or 

 destroying the sea-weeds, either by nets or iu any other way, the her- 

 ring is, of course, obliged to seek other and more suitable places, and, 

 consequently, deserts those inlets where formerly it came regularly. 



By experience gained in Bohusliin and other places it is proved that 

 the herring is extremely sensitive in this respect, and deserts old spawn- 

 ing-places entirely if their character is changed. 



Every one, therefore, who desires to keep his herring-fishery in good 



