404 BULLETIN Or THE UNITED STATES FISH COMMISSION. 



Instead of simply placing one set of two milters and one spawner in 

 one pond, I would prefer to place two sets, even in very small ponds, as 

 accidents may occur, and it may frequently happen that a spawner can- 

 not discbarge her eggs, or that they are not in a healthy condition. 

 And in that cast; persons having only one pond, containing: a single 

 spawner, would not obtain any young fish at all ; there is, of course, less 

 chance that two spawners will both meet with an accident, and, on the 

 Avhole, it will hardly ever hurt to have too many young fish, as there 

 are many ways of diminishing their number. 



The result of the experiment made in the second pond, which, accord- 

 ing to the former practice, contained more spawners than milters, can- 

 not be adduced in favor either of a preponderance of spawners or a 

 preponderance of milters, as, owing - to their small weight (at most 1 

 kilogram apiece), a large portion of them were not fully matured for 

 spawning, and as consequently it was impossible to ascertain how 

 many females and how many males engaged in producing young fish. 

 But even if this were possible, there would absolutely be no means of 

 ascertaining how many young fish would fall to the share of one set. 



Although it is hardly possible that any one but my friend referred to 

 above would conceive the idea of stocking a pond of 322 square meters 

 with 1 00 spawning fish, the result of the experiment made in the second 

 pond proves this, at least, that it is not necessary only to limit the 

 number of fish in a pond to one set in order to obtained a large quantity 

 of small fry, but that the more spawning fish are placed in a pond 

 the more young fish will be obtained from such a pond. 



The experience of Mr. Gasch (the average size of his spawning ponds 

 is 34 ares) and the results of the experiments made in the first pond 

 prove that even in a very diminutive pond enough eggs can be produced 

 to supply a large pond farm, and that a sufficient quantity of young fish 

 can be hatched from them. 



Any pisciculturist can convince himself, by carefully observing the 

 spawning-ponds during the spawing and hatching season, that there is 

 never any lack of eggs and young fish in large ponds. But the dangers 

 to which they are exposed, and against which there is hardly any protec- 

 tion, cause the destruction of by far the larger portion of the eggs and 

 young fish. 



Although I think that there are very plausible reasons for composing 

 the set of more milters than spawners, I cannot, so far at least, abso- 

 lutely reject the opposite plan of our older pond-culturists, which has 

 pi many places been retained to the present time. I first want to know 

 what reasons influenced pisciculturists in olden time to follow this method 

 as it seems hardly probable that their following it had been purely 

 accidental. Unfortunately, no light is thrown on this subject either by 

 ancient or modern writers. In JloraJc's " Teichwirthschaft" (Pond-cul- 

 ture) we find in the chapter entitled " Strciclitcichc" (Spawning-ponds) 

 only one reason given why one should associate only three, and not four, 



