X.-POFULAR EXTRACTS FROM THE INVESTIGATIONS OF THE 

 COMMISSION FOR THE SCIENTIFIC EXAMINATION OF THE 

 GERMAN SEAS. 



[Published by the Royal Ministry of Agriculture, Domains, and Forests.*] 



PREFACE. 



The following" treatise has been prepared at the special request of the 

 Minister of Agriculture, &c, with a view to making some of the more 

 important results of our investigations accessible to practical fishermen, 

 and for the purpose of encouraging them to aid us by all the means at 

 their command in continuing our work in the interest of the salt-water 

 fisheries. 



[The Ministerial Commission for the scientific examination of the German waters : H. 

 A. Meyer, K. Mobius, G. Karsten, V. Hensen.] 



A.— THE PHYSICAL CONDITION OF THE BALTIC AND THE 



NORTH SEA. 



Atfirst sight the knowledge of the condition of the sea- water seems to be 

 of small importance for the practical salt-water fisheries. Fishing has 

 been carried on by men for a long time without any special regard to the 

 temperature, saltness, and currents of the sea ; experience and accident 

 taught men the seasons and places where fishing could be carried on 

 with hopes of good results. No one thought of inquiring whether the 

 success of the fisheries, varying every year, had something to do with the 

 changes in the condition of the sea- water ; and yet it is an undoubted 

 fact that an intimate connection exists between the two. It is not 

 purely accidental that many plants and animals found in a belt extend- 

 ing from the eastern shores of the North Sea to the western shores of 

 the Baltic vary greatly in size and strength, according to the more or 

 less plentiful food or the larger quantity of solid particles in the sea- , 

 water ; nor is it accidental that the changing condition of the water in 

 one aud the same place produces a varying development of plants and 



* Gemeinfassliche Mittheilungen aus den Untersuchungen der Commission sur wissensehafl- 

 lichen Untersuchung der deutschcn Meere. Herausgegeben im Auftrag des KonigUchen Min- 

 isterinms fur Landwirthschaft, Domdnen und Forsten. Kiel, 1880. — Translated by Her- 

 man Jacobson. - , 



