402 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



either two sets will form, each composed of three milters and two 

 spawners, or three sets, each composed of two milters aud one spawner, 

 which arc sufficient in either case to furnish more young fish than are 



needed even for a very large pond-farm, even if the eggs of the remaining 

 live or six spawners should not become impregnated. The reason why 

 there are frequently not enough young fish is, in my opinion, to be found 

 in the circumstance that the spawning-ponds are too large or unsuitable 

 in other respects ; and if only one set of fish were placed in such ponds, 

 no young fry, or at beast but a very small quantity, would be obtained. 



It must be said in favor of the old method (of composing each set of 

 fish for the spawning-ponds of more spawners than milters), which at 

 present is followed in most pond-farms, that two spawners, supposing 

 them to be entirely equal in every respect, will of course produce twice 

 as many eggs as one; but, on the other hand, though there is nothing 

 to disprove such an assertion, it is very doubtful whether both spawners 

 have become impregnated by one milter. 



As no signs of either bigamy or polygamy have as yet been observed 

 among fish, especially among carp, whilst it has often been noticed that 

 several males will engage in mortal combat over one and the same female, 

 I am rather inclined to think that if two females were associated with 

 one male, one of the former would find herself neglected. Moreover, it 

 can hardly be supposed that wheu the fish are at liberty in a large basin 

 of water, the milt of one male is sufficient to impregnate the eggs of sev- 

 eral females, and that the male husbands his milt as much as a piscicul- 

 turist, who thereby succeeds in making the milt of one male suffice for 

 the impregnation of the eggs of several females. Experience litis t aught 

 men to abandon the wet method of impregnation for the dry method. 

 According to this experience, however, it would seem most profitable to 

 have the set composed of more males than females, if a large quantity 

 of fry is aimed at. 



On the other hand, I can positively see no reason why one set offish 

 in a pond should furnish more young fry than several sets, as the very 

 laws of nature seem to forbid it. It is undeniable, however, aud well 

 known from olden times, that small ponds are the best for producing 

 young fry. The reason is this, that they are generally flat, and do not 

 contain much vegetation, that consequently their water is much warmer 

 than that of large and deep ponds, and that there is less chance of eggs 

 and fry being injured, especially by the various enemies of fish. There 

 is this additional advantage, that they are easier to superintend, and 

 that the eggs and fry can be better protected from dangers. But no 

 sound reason can be advanced in proof of the assertion that oue set of 

 fish in a pond will produce more young fry than several sets. 



The following may serve as a contribution towards the practical solu- 

 tion of the problem. A friend of mine, who had so far only engaged in 

 raising salinonoids, wrote me under date of August 9, 1881: 



" My young carp have almost rendered me desperate. On the 1 st June, 



