136 KEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



on tlio lower jaw of the codfish, the haddock, and the glyskoljan. 

 The pollock and the bhmksej {Gadus pollacMus) both have the lower jaw 

 projecting farther than the upper jaw, and are thereby distinguished 

 from the above-mentioned fish found in the Sound and the Baltic, which 

 likewise belong to the cod family. The i^oUock is again distinguished 

 from the blanksej {Gadus pollaclilm): the former has a cloven caudal 

 fin, its sides are almost straight, and its color gradually changes from a 

 dark sea-green on the back to silver-gray on the belly and sides ; the 

 latter has a caudal fin, which is but little indented, its sides are sharply 

 bent, and the brownish-black color of the back is clearly defined from 

 the sOver-gray of the sides. 



The codfish proper never reaches the same size in the Baltic as on our 

 western coast or the coast of Norway. Whilst in the Xorth Sea and 

 the Western Ocean it grows very large, and often reaches a weight of 40 

 pounds, the Baltic cod seldom weighs more than 15 pounds. Like the 

 herring, it gets smaller and smaller the farther north in the Baltic it is 

 found. The average weight of the codfish found in the Southern Baltic 

 and the Sound varies from 3 to 6 pounds, whilst near Gottland it is only 

 2 to 3 pounds, and on the coast near Stockholm only 1 to 2 i)ounds. 



The color of the codfish varies considerably, owing chiefly to the dif- 

 ference of food and the different bottoms on which it lives. Generally 

 the upper parts of its body have an ashy-gray or olive color, thickly dot- 

 ted with round spots of a yellow or brownish hue, decreasing in number 

 towards the sides ; the lower part of the body is whitish, without any 

 spots. The varieties which are found most frequently are the so-called 

 " Berg "-cod, in Bohulsiin, which has a reddish color, thickly covered 

 with spots, and having reddish or grayish -brown fins and back; the 

 "Pall "-cod, near Gottland and the "Berg "-cod of the Southern Baltic, 

 whose whole body is of a dark color with but few spots. The full-grown 

 codfish prefers deep water, either on the outer coast or in large bays 

 and inlets, and only during the spawning-season it temporarily goes into 

 shallow water. It spawns at different times on the different coasts : in 

 the Sound in March, on the coasts of Skdne and Bleking from the mid- 

 dle of March till the end of April, near Gottland and on the coast of 

 Stockholm during April and May. When the spawning-season ap- 

 proaches, the codfish ascends from the deep to shallow waters, either on 

 the outer coast or in bays and inlets. There is this i)eculiarity about the 

 roe of the codfish, that it does not adhere to aquatic plants and stones 

 like that of other Baltic fish, but, according to observations made by 

 the Norwegian naturalist G. O. Sars, floats about freely near the sur- 

 face of the water. Even with a low temperature of the water the eggs 

 are hatched after 18 days, and with a higher temperature, even in a 

 shorter time. After being hatched, the young fish continue to float 

 about near the surface of the water at least as long as they still have 

 the umbilical bag which most young fish carry for some time after being 

 hatched. This bag serves as the food of the young fish ; and as soon 



