5-NOTES ON FISH-CULTURE IN GERMANY. 
NOTES BY S. JAFFE ON INTENSIVE POND-CULTURE AT SANDFORT. 1 
In my pamphlet entitled u Trout-culture ” (published by Eockhorst, Osnabriick), 
I have earnestly warned persons who carry on pond-culture on a small scale not to 
introduce into their ponds artificial food that can not be reproduced in the pond itself. 
They should till their ponds the same as their fields, and stock them only with fish 
which the water of the pond will feed without much aid. They should cultivate and 
increase the live pond-food by introducing snails, mussels, small crustaceans, and 
useful aquatic plants, but should avoid all dead food. 
Wherever water, food, and energy are found, there is no reason why intensive pomi- 
culture should not be carried on. I would, however, lay special stress on the fact that 
this pond-culture can become remunerative only where there is ample water, food, and 
time. The principles laid down in this treatise have been successfully followed at 
Sandfort and other establishments founded on the same plan. 
The water of an establishment where trout are to be raised for market should 
come from ample and steady springs ; the ponds should be near, but not too close to the 
springs, which near their origin contain very little oxygen. It is useful to introduce 
brook or river water into the pond, so as to occasionally render the water turbid; 
but river water alone is rather hurtful on account of the rising temperature. To make 
the water in the ponds occasionally turbid is useful, not only because the particles 
of soil which are precipitated act as a disinfectant on the remnants of food, but also 
because they furnish the trout, particularly in cemented and other entirely arti- 
ficial basins, those particles of earth which they need for the mechanical process of 
digestion. After the water has been turbid for a short while, trout have invariably 
been observed to take to their food with particular readiness, and probably not merely 
because they had to fast while the water was turbid. 
It is difficult to state the minimum quantity of water for a raising-pond; the tem- 
perature, the saturation of the water with oxygen by a strong fall, and other circum- 
stances will render changes in the quantity of water necessary; but no fish- cultural 
establishment should be started without a steady total influx of 0.5 cubic meter (17.7 
cubic feet) of water per minute. 
If the ponds can get shade during the hot afternoon hours from rising ground in 
the neighborhood they will be all the cooler, but the condition which will exercise the 
greatest influence on the quantity of fry to be put in the ponds, and on their safety, 
1 Intensive Teichwirthschaft. Von S. J ail'd in Sandfort. From Allgemeine Fischerei-Zeitung, 
No. 24, 1894. H. Jacobson, translator. 
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