BULLETIN OF THE UNITED STATES FISH COMMISSION. 303 



hatcliiuii-period, but where the line is to be drawn is more than I can. 

 say. We have no such chance for making such tests with the young of 

 whitefish, as they are, of course, lost sight of when released in such vast 

 bodies of water as the great lakes, and we can therefore only speculate 

 as to their probable future. But if varying periods of incubation make 

 no ditterence in the vigor or appearance of trout alevins, why should it 

 with wliitellsh I Do not the facts in connection with trout establish a pre- 

 cedent, or basis, for calculations in regard to the number of adults to be 

 produced from a given number of any kind of fish set free in waters to 

 which they are indigenous, provided the latter are, like the former, 

 protected from enemies, and have an abundance of their appropriate 

 aliment at command ? Is there anything wanting to make the in^emises 

 and conclusions analogous? It is not possible to i)rotect the little fishes 

 from their enemies, when they are turned loose to " seek their own salva- 

 tion.'' But it s/<o«Z^ be incumbent on the flsh-culturist to see to it that 

 they are released only when and where their particular food is found; and 

 not only found, but in sufiicient quantities for the purpose, so that we 

 might reasonably expect as large percentages to survive, outside of those 

 destroyed by enemies, as we do of those grown in our ponds. 



It is one thing to hatch a large number of fish ; it is quite another to 

 know just when and where to place them within the jurisdiction of con- 

 ditions absolutely essential to their existence. The former is now a matter 

 of comparative ease; but as this amounts to nothing, so far as the results 

 sought after are concerned, if the proper conditions are not subsequently 

 supplied, there ought to be a certainty, which scientific investigation 

 alone must determine, that these conditions do exist. The tendency with 

 lish-culturists generally has been to see how many fishes can be brought 

 into existence, and to see how cheaply it can be done, then planting them 

 with a reckless indifference, trusting to "luck" for good results. 



Perhaps, though, this random and indiscriminate distribution is the 

 best that can be done in many instances where the exact requirements 

 are not known. 



Professor Forbes' recent researches to determine the food of the young 

 of whitefish throw a good deal of light on this subject, that will apiily 

 with equal force, in some respects, to other fishes ; and his prospective 

 experiments will doubtless reveal still greater light, if indeed they do 

 not, incidentally, settle the question of prematurity so far as the young 

 of whitefish are concerned. What he proposes to do, as I understood 

 him in a recent conversation on our way from Eacine to Chicago, is to set 

 two or more seines or jiriSons in Geneva Lake, Wisconsin, where the 

 alleged food of the young Avhitefishes, entomostraca, &c., is found. 



Into these separately will be put some fry from the Korthville hatch- 

 ery — if I can keep them alive until he is ready for them — and some 

 from the Detroit hatchery, later on. If the little fellows partake of the 

 entomostraca freely and thrive, this will verify Mr. Forbes' prior conclu- 

 sions that this is their earliest food. If the Detroit fish live and mine 

 do not, it will look as though mine were premature, unless indeed they 



