9 -CONTRIBUTIONS TOWARD THE IMPROVEMENT OF THE CULTURE OF 
SALMONOIDS AND CRAWFISH IN SMALLER WATER-COURSES.* 
By KARL WOZELKA-IGLAU. 
[From “Deutsche Landwirthschaftliche Presse,” Nos. 28 and 31; Berlin, April 6 and 17, 1895.] 
The present management of our smaller water -courses, of streams of different 
size, but containing a quantity of water sufficient at least for the steady working of 
a flourmill or sawmill, leaves a great deal to be desired in the matter of fish or 
crawfish culture. We can hardly speak of the cultivation of these water-courses 
(frequently the finest and most suitable streams for trout) in the proper sense of the 
word. In most cases they are left to themselves; and only between the different 
falls are fish and crawfish — if the stream contains enough to make the labor remuner- 
ative — caught with nets, reels, etc.; occasionally also by laying the milldam dry. 
In very few cases is the stream stocked with young fish or spawn or mother crawfish, 
and then only to maintain the actual supply of fish or crawfish. 
These natural streams can never, or at best only partially, be laid dry; fishing 
can not be carried on systematically, and a proper management is consequently out 
of the question. We therefore find in those streams which have a large supply of 
fish, besides crawfish of every age, predaceous fish and other fish of many varieties 
and different sizes. Under such circumstances the stock of fish aud crawfish can 
never be fully developed, because a constant war is going on between the different 
inhabitants of these streams, with a consequent reduction of numbers. The water 
could frequently contain a much larger quantity of fish or crawfish if they were only 
allowed to increase in number. Cultivated fish, in the full sense of the term, are not 
known in these waters. The spawn deposited by the more valuable fish (trout, 
grayling, etc.) is partly devoured by crawfish and partly destroyed by bullheads, 
gudgeons, etc. Natural occurrences (floods, drought, heavy ice, etc.) also contribute 
their share toward diminishing the spawn. Artificial impregnation, hatching, and 
the careful raising of the young fish and crawfish will be thoroughly appreciated if 
we bear in mind that of the spawn or young crawfish deposited in natural waters 
hardly 5 per cent are developed into full-grown fish or crawfish. If young fish or 
crawfish are placed with larger animals of their own kind, it may be assumed with 
absolute certainty that in a very short time 70 to 80 per cent will be destroyed. 
What is the use, therefore, of careful cultivation under such circumstances ? 
* Beitrag zur Hebung der Salmoniden- und Krebszuclit in kleineren Wassergerinnen. — H. Jacob- 
son, translator. 
Note. — This article is presented in the hope that it may afford suggestions for the utilization of 
some of the waters of this country, even though all the conditions mentioned as present in the streams 
of Bohemia may not exist in those of the United States. 
F. C. B. 1895—24 
369 
