practical papers—fish Culture. 
4 11 
take a thousand years or more, and the reason is this : The sal¬ 
mon-trout inhabit the deep water of the lakes, in common with 
the white-fish, and their food is to a large extent made up of the 
young of the white-fish. Now, because the white-fish are more 
highly esteemed for the table, and are more easily taken than the 
salmon-trout, they have been decreased in greater proportion than 
the salmon-trout. In its natural state the lakes held so many 
breeding white-fish that the salmon-trout did not perceptibly de¬ 
crease their numbers; the balance was maintained ; but with the 
decreased number of white-fish breeders, and comparatively larger 
number of salmon-trout, the balance is lost, and the salmon-trout 
will keep the white-fish down. 
The other method is by artificial hatching. If enough young 
fish are put into any one lake, the abundance of twenty years ago 
can be restoied in four years. Let us take, for instance, Lake 
Erie. Most of the experiments already made with white fish 
have been tried there; that is, experiments in obtaining and im¬ 
pregnating eggs. The fish run up into the Detroit river to spawn, 
and are easily obtained. lienee, at this point (Detroit) the habits 
of the fish at their breeding-time are known, the spawners are 
caught without difficulty, and we have all the knowledge neces¬ 
sary to restocking the lake. For restocking Lake Erie there 
should be put into the lake at least 'One hundred million of young 
fish annually for four years. That these young fish will live and 
grow is not now to be questioned. The fact has been definitely 
settled by the increase of the various shad-fisheries stocked in the 
same way. Of course not all of the number put in will arrive at 
maturity; a large proportion will furnish food to adult fish of 
other kinds, but certainly no larger proportion than is now lost in 
the same way. The proportion destroyed being the same, let us 
see what is the advantage of artificial over natural increase. Out 
of rive thousand eggs laid naturally , one egg (not one thousand) 
will hatch out. Four thousand fish hatched out of five thousand 
eggs is a low estimate for artificial hatching, but even at this low 
estimate the increase of chances is four thousand fish to one fish. 
An appropriation of $15,000 per year for four years by the gov¬ 
ernment would be amply sufficient for the purpose—which appro- 
