XXV.-BIOLOGICAL OBSERVATIONS MADE DURING THE ARTIFI- 

 CIAL RAISING OF HERRINGS IN THE WESTERN BALTIC. 



By Dr. H. A. Meyer. 



PEEFACE. 



I have published my observations on the spawning-seasou of the her- 

 ring, on its growth, the influence of the temperature of the water on the 

 spawn, as well as some other facts relating to the mode of life of the her- 

 ring, in the Annual Eeport of the Commission for a scientific investigation 

 of the German seas for 1874-'76, Berlin, 1878. 



These investigations I have continued during the years 1877 and 1878, 

 in the direction pointed out in that report. As it will be some time be- 

 fore the next report of the commission is published, and as from a prac- 

 tical point of view it will be of interest to make the newly acquired ex- 

 perience quickly known, I publish the following preliminary report, con- 

 taining the more important results of the last two years' observations of 

 the development of the herring. 



I. — INFLUENCE OF THE TEjVIPERATURE ON THE DEVELOPMENT OF THE 

 EGGS OF THE HERRING IN SPRING. 



In the above-mentioned report of the commission, the various experi- 

 ments are given, which go to prove that very cold water will consider- 

 ably delay the hatching of the eggs of the autumn herring. It was stiU 

 an open question whether the same applied to the eggs of those herring 

 which spawn in spring, which could only be settled by making the neces- 

 sary experiments. This seemed all the more desirable, as it was a ques- 

 tion not only of scientific but also of practical interest. If impregnated 

 eggs of those fish of the herring kind which spawn in spring and summer 

 can be preserved in a healthy state for a longer time by keeping them 

 cold, the artificial raising of fish will thereby be benefited, because then 

 it will become possible to send such eggs to distant countries. As the 

 time which it takes the summer spawn to develop under ordinary cir- 

 cumstances is but short, the attempts to import the spawn of valuable 

 American summer fish have so far not been successful. 



* Biolof/ische Beobachtnngen hei KUustUcher Aufzucht des Herings der ivesilichen Ostsee. 

 Von Dr. H. A. Meyer, Berlin, 1878. Translated bv Herman Jacobson. 



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