35 
part of the year in salt-water on our shores; nay, the salmon, perhaps, lives 
even pretty far from the shore, it is not known exactly where. These fishes 
then migrate withm our district, and must be classed with the stationary 
fishes, as we take the word here. 
Of the other fresh-water and brackish water fishes, properly so called, 
which live in the Baltic at some distance from the shores: the pike, the 
perch, and Leuciscus idus, I shall here say nothing particular; they are 
perhaps, in part, to be looked upon as migratory fishes from the Baltic Sea. 
The Migratory Fishes may also be divided into several groups: 
a) The genuine migratory fishes, garfish and mackerel, which appear on 
our shores only for a short time (the former in order tø spawn), and which 
again completely disappear from them before the end of the year. Their 
migrations are so obvious that they have been known for many years, and 
have never been misconstrued. These fishes, most probably, live out in the 
Atlantic Ocean during the winter. 
Certain other fishes, particularly the herring and the sprat, ought also, 
in part at least, to be classed among the genuine migratory fishes; but they 
may come from the Baltic Sea as well as through the Skager-Rack. The 
biology of the herring, particularly, is so complicated, because there are 
different races, with different spawning-seasons, that it is not easy here to 
ascertain anything precisely. Our seas are never, at any time of the year, 
quite empty of herrings; but, certainly, im great masses they are found 
only when a migration takes place from the surrounding larger seas. In 
spite of all the mathematical science that has been written of the herring 
and its various races, this question is still very far from being solved; but 
it does migrate; and the Baltic Sea herrings are smaller than those of the 
North Sea, that is certain too. 
b) This second group of migratory fishes comprises a number which, 
from some reason or other, do not live all their life in our seas. Either 
the young ones are missing, or there are certain intermediate ages which 
the fish spends outside our waters, or it makes annual migrations in and 
out. The cod is the most important fish that belongs to this group. Its 
fry, at certain young stages, is missing, and the, grown-up fish goes annually 
in and out through our seas. In the Baltic and in the Belts, however, not 
a few remain every year; but, all in all, the cod must be called a strongly 
marked migratory fish. In a somewhat similar way we must look upon 
the haddock, the whiting, the pollack, and the green cod; only they go still 
farther away from us. However strange it sounds, the %alibut, the pole dab, 
and perhaps the /emon dab, must also be classed among the migratory 
fishes.. The young ones of all three are very rare, or quite missing, here; 
and although the two last named of them perhaps do not go far, they go 
far enough at any rate to disappear from the Cattegat into the Skager-Rack 
