CANADIAN FISHERIES EXPEDITION, 191/rlo xv 



find the eggs and larvae of these fish at station 72, where the bottom-temperature was 

 between 2°C. and4-6°C., whereas nearer land, where the bottom-temperature was 0°C, 

 or even less, they were absent."^ 



In 1915, I had the honour of being invited by the Biological Board of Canada to 

 make a stay of some months' duration in that country in order to study the Atlantic 

 herring fisheries of Canada; an invitation which I was extremely happy to accept. I 

 could not, of course, hope to accomplish very much in so short a time, especially as I 

 had no prospect of being able to procure the necessary means for practical research 

 work at sea. The investigations of recent years, however, with regard to the growth of 

 various species of fish — and particularly of the herring — had shown that it was pos- 

 sible, by studying the growth of the fish and age composition of the stock, as expressed 

 in the annual rings of the scales, to form a remarkably close estimate, not only of the 

 biology of the separate species, but also of the conditions in the sea wherein they 

 occurred. It seemed to me, therefore, worth while to see whether such investigations, 

 albeit here necessarily of an occasional and by no means final character, might not open 

 up fresh points of view, and lead to further and more detailed study in the same field. 



The main objects of such scale investigations should then, it seemed to me, be for- 

 mulated as follows : — 



1. Do the herring that visit the Atlantic coast of Canada all belong to a single 

 race or type, or is it possible to distinguish several races in these waters? 



2. Does the rate of growth vary according to the conditions of the waters along 

 the coast? Can types of different growth be distinguished and defined? 



3. Is the renewal of the stock of herring of a constant character, or are there the 

 same great fluctuations in the stock, i. e., in the number of individuals in the different 

 year-classes, as in European waters ?^ ' 



The first two problems, or groups of problems, are of course identical with the 

 problems of the distribution and migrations of the herring. If the Atlantic stock of 

 herring can be shown to belong to several different races, then of course the area of 

 distribution and migration of each race or type may be defined by a study of samples 

 of herring taken from different localities along the whole coast. 



The third problem is of the greatest importance for any elucidation of the old 

 riddle — the fluctuations in the yield of the fisheries — this being to a very great extent 

 dependent upon the fluctuations in the number of herrimgs living in the sea at the 

 time. 



On arriving at Halifax, therefore, in October, 1914, I first of all endeavoured to 

 organize a collection of material. I had no other means at my disposal than such as 

 could be contained in the not very extensive luggage of an ordinary traveller, and it 

 was thus useless to think of anything beyond samples drawn from the catches brought 

 in by the fishermen' themselves. In other words, my material would have to consist 

 of salted herrings purchased from various localities. Thanks to the very kind assist- 

 ance afforded me by the Biological Board, especially by the Dominion Commissioner 

 of Fisheries, Prof. E. E. Prince, and by Prof. A. B. Macallum, Secretary-Treasurer of 

 the Biological Board, who endeavoured by every means in their power to facilitate my 

 researches, I succeeded in obtaining samples from various parts of the gulf of St. 

 Lawrence, and from Newfoundland. It was necessary, however, to form some idea 

 as to the representative value of the samples thus obtained, and with this end in view 

 I made a .iourney along the coast, in the autumn of 1915, and over to Newfound- 

 land, visiting the fishing stations, and taking every opportunity of ascertaining, by 

 conversation with the fishermen, what kind of implements were employed for the 

 capture of herring, and what experience the fishermen themselves had acquired as 

 to the occurrence of the fish. In some places, I was able myself to study the fishing 

 in progress, and examine the implements used. The fishermen everywhere, almost 



1 Loc. cit. p. 106, and following. 



2 See my paper : Fluctuations in the Great Fisheries of Northern Europe. Rapports et 

 Proces-Veirbaux, Vol. XX, Copenhagen, 1914. 



