PROPAGATION AND PROTECTION OF THE RHINE SALlitON. 825 



represent for the fishermen of the upper regions, most of whom belong to the 

 poorer classes of society, a precious contribution to their earnings. The higher 

 the fish ascend, the narrower the tributaries and brooks, the easier to catch 

 the big fish, which in their particular condition are, moreover, slow and lazy 

 in their movements. In consequence very few fish escape; in other words, the 

 number of those spawning in the natural way is as a rule extremely small. I 

 I do not hesitate to say that if the keeping up of the stock of salmon depended 

 on natural propagation only the salmon production of the Rhine by this 

 time would be very poor. 



Artificial propagation has tried, and I think not without success, to remedy 

 this deficiency. A good many of the salmon caught in ripe condition, or nearly 

 so, in the upper regions of the river are used for artificial hatching and from these 

 several millions of fry have been produced annually for many years. They have 

 been set free in the most suitable waters, that is to say, mostly in those smaller 

 brooks and tributaries where the salmon would have spawned in the natural way 

 if man had not interfered with their intentions. An arrangement was made, first 

 by Baden, Switzerland, and the so-called Reichsland (Elsass-Lotharingen) and 

 a few years later (1890) by Holland, the different German states bordering on 

 the Rhine, and Switzerland, annually to set free a certain number of salmon 

 fry, and quantities varying from 4 and 6 to 7 millions of young salmon accord- 

 ingly were bred each year. They are planted almost immediately after the 

 resorption of the yolk vesicle, sometimes also a little before the young salmon 

 have developed so far. They are distributed over a large area of the upper 

 course of the river, and, as I pointed out before, if possible at such places only 

 as salmon are accustomed to seek to spawn in the natural way. Against this 

 procedure an objection was raised that the distance between these spawning 

 places and the open sea is a long one, and that numerous dangers threaten the 

 young fish during their stay in the upper parts of the river and during their 

 descent to the sea as well. It looks at first sight as if these dangers might 

 be avoided by cultivating the fry near the mouth of the river and by keeping 

 them longer in tanks or ponds at the hatchery; but as only very few ripe fish 

 are taken in the lower parts of the river, the culturist is obliged to collect 

 unripe salmon several weeks before the spawning and to keep them in reservoirs 

 floating in the river until they are ripe; or, if he does not like that way of 

 doing, to order eggs from the upper parts, which eggs, once the eyes of the 

 embryo have become visible, endure the transportation well. 



Comparing this way of proceeding with the culture at or near the spawning 

 places, and keeping in mind that it is a well established fact that in free nature 

 the young salmon in the upper regions of the river live at least one year the 

 life of young trout, since studying the salmon and the salmon development 

 I have always been convinced, and am still at the present time, that the most 



B. B. F. 1908— Pt 2—10 



