WIDEGREN MANAGEMENT OF THE BALTIC FISHERY. 127 



place, the whole process probably occupying uot more than five or six 

 hours. The roe is laid on aquatic plants, stones, pebbles, &c. The de- 

 velopment of the roe occupies a shorter or a longer time, according to 

 the different temperature of the water. 



In May, when the water is colder, it takes ll to IS days to hatch the roe, 

 but in August and July, when the water in the spawning-places generally 

 has a temj)erature of 14 to 15 degrees (0.) (57.2°-59° F.), it only requires six 

 to eight days. The newly-hatched young fish , which are smaller and more 

 transparent than most other young lish, and are, therefore, hard to dis- 

 tinguish, are a little over J inch long, and have, for eight days after the 

 hatching, a bag attached to then" body, which hinders the young herring 

 from being very brisk in its movements during the earliest part of its 

 life. Only after the young fish has lost this so-caUed umbilical bag it 

 begins to swim about, gather in schools, and seek food. It is difficult to 

 ascertain with absolute certainty the growth and size of the young her- 

 ring at certain periods of its life, especially as not all the young fish 

 have the same ability to gather food, on which circumstance their growth 

 of course depends. 



Attempts have been made to raise young fish by x^laciug them in 

 small basins and feeding them regularly, but so far these attemj^ts have 

 proved unsuccessful, as the young fish did not live longer than five 

 weeks, at which time they have reached a length of about ^ inch. 

 During the w^hole first year of their life the young fish may be found in 

 the spawning-places, both on the outer coast and in the inner bays. 

 Young fish, measuring 1 inch in length, may be supposed to be about 

 two months old; at the age of three months thej^ measure about 1^ inch 

 in length, all the fins are completely developed, and the color of the 

 body resembles that of the grown herring, so that they may be easily 

 recognized as the young of this fish, which formerly could not have been 

 done. After examining young fish found in the spawning-places one 

 has felt justified in concluding that the young herrings measuring about 

 3 inches in length, which in spring are found in the spawning-places, are 

 those fish which have been hatched earliest during the preceding year, 

 and are, therefore, about a year old. The young fish measuring 5 to 6 

 inches in length, which are often caught in nets, are therefore supposed 

 to be only two years old. When a fish has reached this size the roe and 

 milt begin to develop rapidly, and when it has reached a length of 8 

 inches it is capable of propagating, and may then be supposed to be 

 about three years old. 



The food of the young herring, as well as of the full-grown herring, 

 consists chiefly of small crustaceans scarcely discernible with the naked 

 eye, which are found in large quantities in the water both in shallow and 

 deep places. By towing in the sea-water with a net made of fine gauze 

 large numbers of these little animals may be caught. They are more or 

 less plentiful at difterent times and under different conditions of weather, 

 and at different depths. This may possibly explain to some extent the 



