128 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



fact that the herrings are not always foiiud at one and the same depth. 

 In snmmcr these' small crustaceans are found nearer the surface, and the 

 herrings at this time likewise go nearer the surface. Like other fish, the 

 herring abstains from food for some time before and after spawning, and 

 its stomach is then generally empty, but after spawning it begins to take 

 food again, and gradually recovers the strength and fatness which it had 

 lost during the spawning process. This explains why the herring is fat 

 at one time of the year and lean at another. 



About two months before spawning commences the herring may, as 

 a general rule, be said to be fattest and best. This fatness it retains 

 almost to the end of the spawning-season, w^hen it begins to get lean, and 

 when it is not fit to be caught. The herring, after having done spawn- 

 ing, usually goes into deeper water in order to seek food, and does not 

 return until it has entirely recovered its strength. That the herring, like 

 other fish, returns to the place where it was born as soon as it has become 

 capable of projiagating is proved by the ftict mentioned above that certain 

 schools or tribes of herring spawn at the same place every year. That 

 the number of fish is one year larger in one place than in another is 

 doubtless caused by changes in the weather, ciuTcuts, &c. Similar 

 causes may even produce an almost total failure of the herring-fisheries 

 in some locality. Cold and unfavorable weather during the spawning- 

 season doubtless often kills large numbers of the young fish of some 

 school, which of course will afi'ect the herring-fisheries for several years 

 to come. These and other-circumstances on which the herring-fisheries 

 depend have so far been so little explained that not much can be said 

 regarding them ; but it is fully known and understood that man may 

 destroy the herring-fisheries in some portion of the sea not only by using 

 nets which will catch both old and young fish, but also by disturbing the 

 spawning-places. 



It has been mentioned before that certain tribes of herring, especially 

 the larger ones, spawn near the coast on bottoms overgrown with algte. 

 If this bottom is made unfit for spawning by pulling out or otherwise 

 destroying the algte by dragging nets along the bottom or in anj^ other 

 way, the herrings are forced to seek other and more suitable places for 

 spawning, and they consequently leave these waters which they used to 

 visit regularly. Experience gathered in Bohusliin and other i^laces has 

 shown that the herring is very sensitive in this respect, and leaves its 

 old spawning-place entirely if its nature is changed or disturbed. Every 

 one, therefore, who wishes to protect his fisheries should be very careful 

 not to change the nature of the spawning-places, either by disturbing 

 the growth of the algae or other aquatic plants or by throwing refuse or 

 impure matters in the water. 



Different methods of catcJiing herrings. — From what has been said re- 

 garding the nature and mode of life of the herring, it will be seen that 

 in order not to destroy the whole tribe by catching the young fish or by 

 disturbing the spawning-jjlaces, it will be best not to use nets during the 



