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fry of the common cod. Also the fry of the pollack is found here (Hjort). 
For the present I shall say nothing of our rarer codfish on deeper water 
in the Cattegat, Gadus minutus, the hake (Merlucius smiridus), and the 
ling (Molva vulgaris). There remain then of codfish only the rocklings 
(the genus Motella (Onos)) and the paddoch (Raniceps vulgaris). Among 
the former we meet the peculiarity that it is easier to find the fry in 
our seas than the grown up animals. This is not the case with the 
paddock. The grown up animals are always caught singly only in our in- 
shore waters. In the deep Skager-Rack, on 70 fathoms, I have, on the other 
hand, taken as many as 7 Motella cimbria in one haul with an otter-seine. 
The grown up fish, however, are as I have said otherwise so rare that it 
is, at present, impossible to enter more closely on their biology. Ås they, 
most likely, spawn later in the year than the other codfishes, consequently 
when the currents lead into the Cattegat, this is perhaps the reason why 
the fry is so numerous here. 
When you have for some years been studying flat-fishes: plaice, floun- 
ders, dabs, etc., as I have been doing, and then sets to work upon the 
codfishes, you soon feel that the latter are much more inconstant. The 
investigations must be carried on in quite another way. If, after some time, 
you return to a fishing-ground you have formerly investigated, you often 
find everything changed, the fish have gone, and you do not under- 
stand anything of the whole matter, till some day the explanation flashes 
upon you: migration and migration and once more migration. Our seas 
within the Skaw are small, not longer than many Norwegian fjords, about 
which we know now, that they are, at times, filled with cod, and at other 
times quite empty of them. It lies near, therefore, to suppose that shoals 
of cod at certain times enter the fjords, and that they leave them again at 
other times; particularly so, as we have long known that other fishes such 
as garfish and mackerel do the same. — When we have seen, on the 
shores of Norway, how the green cod in immense shoals, at the utmost 
rocks, chases various "Åater”, and how it goes far away from the bottom 
on these hunting expeditions, often scouring the sea with their fins above 
the surface of the water, so that this is all in a foam, while the seiners 
who are on the watch, must row out their seines with the greatest possible 
speed, if they want to catch part of the shoal, then we can understand also 
that the cod, the near relation of the green cod, though not so swift a 
swimmer, very well may undertake long migrations, and that it is not at 
all such a dull bottom-fish as it has sometimes wrongly been said. Nay, Dr. 
Hjort has even proved, that large cod can live pelagically out in the surface- 
waters of the Norwegian North Atlantic, over the great depths, whose tem- 
perature at the bottom is below zero, so that it is impossible that the cod 
can here have anything to do with the bottom. 
But while Hjort feels convinced "that these fish in large multitudes migrate 
over the great depths”, I must, as matters are now before us, rather doubt the 
