160 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



II. 



BRIEF EEVIEW OF OUR PRESENT KI^OWLEDGE OF THE 

 MODE OF LIFE AND THE MIGRATIONS OF THE HERRING, 

 AND THEIR PHYSICAL AND BIOLOGICAL CAUSES. 



1. The rich herring-fisheries which took place on the coast of Bohus- 

 lan at the end of last year (1877) and the beginning of the present year 

 (1878) have caused me to publish a brief statement of the present con- 

 dition of the scientific investigations regarding the mode of life of the 

 herring and its annual and other migrations, as well as of those nat- 

 ural conditions which may be their causes. I have done this with the 

 special object of making the scattered scientific material accessible for 

 the general public, as this certainly would be of practical use in case the 

 herrings should again regularly visit our western coast in any consider- 

 able numbers. The amount of knowledge we possess is small ; but if 

 brought within the reach of a larger pubhc it may nevertheless have a 

 beneficial influence on the fisheries. So far, we do not possess any sci- 

 entific collection of all the material j^repared with a view to the spe- 

 cial needs of our coast; just as little any general and comprehensive 

 epitome of it. In order, therefore, to make this treatise as timely as 

 possible I have collected aU the facts in my possession, and by compai> 

 ing them with the results of the most recent foreign investigations I have 

 endeavored to make them as complete and reliable as possible, which, 

 however, has not materially changed my previous views. These more or 

 less strictly scientific investigations have so far not produced any result 

 which could lead to a complete and much-needed reform in this branch 

 of human knowledge; but in most points our knowledge is just as incom- 

 plete and as little critically sifted as it was a hundred years ago. 



2. The object of this entirely preliminary review of our present knowl- 

 edge of the mode of life and the migrations of the herring is, first j to give 

 in as brief and as clear and systematic a form as possible aU the mate- 

 rial which has gradually accumulated in the course of time, in order to 

 make it more accessible both to scientists and to fishermen ; second, to 

 give a review of the historical development of the more important points 

 in our knowledge, in order, if possible, to prevent mistakes in the future, 

 and to facilitate a more correct understanding of all the circumstances; 

 and, tUrd, to show the necessity and to point out the course and possible 

 results of continued scientific investigations. An entirely satisfactory 

 scientific review of aU our knowledge presupposes an ample amount of 

 material critically sifted, consisting in observations made uninterrupt- 

 edly during a long period of time at a large number of places; for, as in 

 meteorology, all truly scientific knowledge must be based on a collection 

 and comparison of as large a number of observations as possible, made 

 by reliable persons during a long period of time and in many different 



