[79] POND CULTURE. 545 



of ;i f'ood stock of youug fish. The result of ])ropagation can never he 

 calculated with absolute certainty; and it is, therefore, advisable to 

 slock the pond with a large number of spawning fish. Formerly it was 

 considered a misfortune if young- fry occurred in the stock ponds, for 

 they will diminish the quantity of food in the ponds. But times have 

 changed, new objects have arisen, and the methods have consequently 

 been compelled to undergo a change. It will certainly do no harm to 

 place a few spawning fish in every pond, if one only takes care to watch 

 and ascertain the quantity of j'oung fry, so as to be sure to make the 

 supply of food ample. Even if occasionalh' there shonld be a surplus of 

 young fry, this will always find buyers; and by supplying it with the 

 necessary food it may be retained and sold Avhen the young fish have 

 reached the age of three years."* 



Although I agree with Delius in his first remarks, I nuist consider it 



something of a venture to ijlace spawning fish in all the ponds, by which 



he can mean only the raising and si)awning i)onds, as in the stock ponds 



theyonng fry would become the prey of the pike, and I would iH)t advise 



this, except in case of absolute necessity. I cannot share the fear that 



the qnantity of food would be diminished by the young fry, but I rather 



fear that the young fish will get too little food, as experience teaches 



that the large fish drive the little ones away from the feeding-places and 



rol) them of their food. Moreover the young fry would not find that 



rest which is so necessary for their proper development, if there are 



many other fish in the same pond. Although rarely, it nevertheless 



occurs sometimes that three-year or four-year old fish spawn in the 



raising ponds. In that case the young of these immature fish would 



mingle witli those of the sijawuing fish. ISTo young fry produced outside 



of the spawning i)onds, even if ever so fine, should be used for raising. 



In order, therefore, to make sure of a sufficient quantity of young fry, it 



shonld be distributed over a number of small spawning ponds, which 



shonld be stocked with a comparatively large number of spawning fish. 



Whenever young fry occur in stock j)onds, this will in all cases have to 



be considered as a misfortune, as the food necessary for the other fish 



t will be diminished, and because the spawning of the fish decreases their 



I weight. To remedy these evils fish of pre}" should be placed in the stock 



I ponds so as to prevent the tame fish from spawning, and at any rate to 



; decrease the qnantity of young frj'. Although in our times spawn and 



( young fish will find a readier sale than formerly, it can hardly- be deemed 



I advisable to deviate from the above principles. The favorable results 



j which have accompanied the artificial hatching of various kinds of sal- 



! monoids have led j)cople to think that the same method might be em- 



' ployed with the carp; but the attempts in that direction have ])roved 



I successful only in rare cases, the main difficulty being the adhesive 



' quality of the eggs. As it is not our object to treat of artificial liatch- 



iug, it will not be necessary to enter further into this matter. It will 



* Delius, Teidiwirthschaft, p. 93. 

 H. Mis. 68 35 



