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to Spitzbergen I did not succeed in catching a single cod. At Bear Island also, the 
occurrence varies greatly. In 1900 I found no cod there; in 1901 however, successful 
fishing experiments were carried out on the edge of the bank, cod of between 72 and 
120 em. being taken. In 1900, the temperature on the bank was = 1.5, in 1901, between 
1° and 2°. I have in course of time obtained a great deal of information from sealers 
as to the occurrence of large cod in the whole of the water between Bear Island and No- 
vaya Zemlya; these occurrences were, however, generally regarded as due to the acci- 
dental presence of quickly moving fish, which are continually changing their position, 
and thus difficult to locate, the encountering of such shoals being largely a matter of 
chance. 
Finally, skrei are also found outside the regular season on the banks off the coasts 
of the Tromso and North Coast districts, more especially, perhaps, out towards the edge 
of the banks. The numerous fishing experiments already made have shown occasional 
occurrence of large fish in summer on all the banks of the northernmost part of the Nor- 
wegian coast. Not only on the banks and out towards the edge, but even beyond, above 
the great Arctic deep, some few wandering large cod have been encountered in summer. 
(See also chart, Fig. 3, Introduction). 
Thus the skrei shoals, after spawning, distribute themselves over the sea banks, 
northward and eastward along the coast over the banks of the Barents Sea. From these 
localities they must again move back next winter, when roe and milt begin to develope, 
southward and westward to the skrei banks. We then again encounter great migra- 
tions, but in the opposite direction. 
Younger stages of cod. 
The skrei are the grown, mature fish, all large enough to be taken with hook and 
line, and as most of the skrei here dealt with were captured in this manner, the samples 
examined may be considered as a representative selection of the actual stock. Investi- 
gation of the size composition of the skrei shoals is therefore a much simpler matter 
than in the case of the younger, immature stages, which do not congregate, as do the 
skrei, at certain spots, and with all sizes mixed together. Among the many different 
sizes, from the young fry up to the stage immediately proceding maturity, we find several 
groups, differing either in biological respects or in regard to habitat and manner of life. 
It is therefore impossible to obtain, in a single sample, any sufficiently representative 
selection to permit of immediate conclusions as to the composition of the mass. It is 
necessary to take many samples from different shoals of fish at different places, endea- 
vouring to combine the ideas obtained so as to form, as it were, a composite picture. 
Moreover, it is in some respects impossible to find any standard by which to judge of 
the respective quantitative values of the different groups, even though it may be pos- 
sible to accurately determine the composition in point of size of each separate group. 
As regards the northern Norwegian waters, if we desire to study the habitat and 
life history of the younger stages, it is necessary to commence with the very earliest 
stages, 1. e. the newly spawned eggs, which, as we have seen, are to be found in the water 
immediately above the spawning shoals, on the skrei banks. We have also seen how 
these newly spawned eggs are transported, at a very early stage, from place to place 
