RON 
at this period of their life, which further confirms the belief that the limits of their sphere 
of movement are now more or less accurately known and defined. 
A considerable portion of the stock annually taken by the fishery. 
The numerous marking experiments which have been carried out during the last 
few years have also gone far to create the impression that the stock of fish in northern 
waters was by no means the vague, indefinite and unlimited quantity formerly supposed. 
The percentage of marked fish recaptured was extremely high, and in the course of the 
last twenty years, scientists interested in the subject have more and more inclined to 
the opinion that the hauls made by the fishermen really represent a very considerable 
portion of the actual stock in the sea. This being granted, it is then possible, by means 
of experimental hauls, and by the study of comparatively few, but methodically collected 
samples, to obtain a reliable view of the stock, as for instance with regard to the relative 
numbers of fish of different sizes therein contained. In this manner, the first foundation 
for scientific study of the stock and its fluctuations was obtained. 
Preliminary investigations as to the cod fishery in northern Norwegian 
waters, I900—1903. 
When the Norwegian research vessel “Michael Sars” was built, in 1900, the fisheries 
of Norway were in a highly critical position. The years immediately preceding had, 
from the point of view of the fishing industry, been distinctly bad, especially in the north- 
ern districts, where the population, whose existence depends almost exclusively upon 
the proceeds of the fishery, were in many places reduced to the direst straits. Innumer- 
able theories and suggestions were put forward to account for the continued failure 
of the industry. The general opinion centred round the belief that the decrease in the 
yield was occasioned by the presence of the whaling vessels which at that time worked 
the waters to the north of the Finmark coast as far as Bear Island. It was at this period 
that I received instructions from the Norwegian Government to investigate, as far as 
possible, the causes of the diminution in the yield. I therefore commenced, in 1900, 
a series of cruises on board the “Michael Sars”, with a view to studying the habits and 
occurrence of the cod in northern Norwegian waters. In the course of this work, which 
extended until 1903, I devoted particular attention to the study of the spawning, and 
the locality and movements of the fish at different stages of developement, collecting 
also a quantity of material to serve as basis for investigation of the composition of the 
stock in regard to size*). I did not, however, then succeed in arriving at any definite 
conclusion as to the causes of the great fluctuations in the fishery or the laws which govern 
the same; this was hardly to be expected in so short a time. The principal result attained 
in the course of the investigations was a first survey of the natural history of the cod, 
(vide Chapter III) and a recognition of the fact that future efforts towards the attain- 
ment of the end in view would need to be concentrated upon the study of the actual 
stock. 
A serious hindrance to the progress of the work in these preliminary investigations 
was occasioned by my committing the error of employing the methods generally accepted 
*) Joxan Hsorr, Fiskeri og Hvalfangst i det nordlige Norge: Aarsberetning vedk. Norges 
Fiskerier, 1ste Hefte, 1903, 
9 
& 
