186 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



la the Baltic, the herring spawns partly in the spring and partly in 

 the summer, and is therefore called spring-herring and summer-herring. 

 In the southern portion of the Baltic, the herring continues to spawn till 

 about the middle of October, while in the northern portion the spawning 

 season closes in August. The spawniug occurs partly outside the coast 

 on elevations of from three to fifteen fathoms from the bottom of the sea, 

 and partly in the fjords (gulfs) nearer to the main land, particularly in 

 places where the bottom of the sea is thickly covered with sea-weeds. 

 Tbe spawning process goes on very rapidly, as the school ouly keeps to- 

 gether at the bottom probably from five to six hours. The spawn is 

 dropped on sea-weeds, stones, sand, and similar objects, where it remains. 

 The development of the spawn takes a longer or shorter time, according 

 to the temperature of the water. 



In May, when the water is cool, it takes from fourteen to eighteen 

 days for the spawn to develop, while in July and August, when the 

 water in the spawning-places usually has a temperature of from 14° to 

 15°, Reaumur, it requires only from six to eight days. The young her- 

 ring, which is smaller and more transparent than the young of most 

 other fish, (and on this accouut difficult to distinguish,) is a little more 

 than one-quarter of an inch long, and has, till about eight days after the 

 development, a residue of the yolk remaining obliquely across the belly, 

 which, at first, greatly impedes its movements. Only when the young 

 herring has lost this so-called " belly -bladder," does it begin to swim 

 around, to collect in schools, and seek food. It is difficult to determine 

 the growth and size of the young herring until it reaches a certain age, 

 especially as all the young ones have not the same ability to gather food, 

 on which circumstance the development of course depends. 



Attempts have been made to raise young herring by having them 

 inclosed in small basins, but they have never lived longer than about five 

 weeks, at which time their length was about one-half of a decimal inch. 

 During the whole first year of its existence, the young herring is found 

 in its spawning place both outside the coast and inside the fjords. Young 

 herring about one common inch in length may be supposed to be about 

 two months old. At the age of three mouths, their length is about an 

 inch and a half. All the fins are fully developed, and the whole shape of 

 the body resembles that of the mature herring, so that it can easily be 

 recognized as the young of this fish, which before that time is somewhat 

 difficult. From comparisons made with the young herring found in the 

 spawning-places, it is safe to assume that those of about 3 inches in 

 length found in the spawning-places in spring are of the preceding 

 year's spawning, and, therefore, about one year old. Young herring from 

 5 to 6 inches in length, which are often caught iu nets, are probably 

 only two years old. In fish of this size the roe and the milk begin to be 

 tolerably developed, and when the fish has reached the length of 8 inches 

 and the age of about three years, it is capable of spawning. 



The food of the young, as well as the grown herring, consists chiefly 



