304 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



shall have been kept too long before the test is made. If the Detroit 

 fish suffer as great loss as mine, it will look as though there was no ad- 

 vantage or nothing to be gained by retarding the eggs, so far as the 

 vigor of the fish is concerned. If Mr. Forbes finds that the entomostraca 

 are much more abundant later on than when he made investigations at 

 Racine the day following our plant of fish at that point, it will signify 

 that we should keep back the eggs, so that the fry may have the greatest 

 Ijossible amount of food at their disposal. Or, if Mr. Forbes' experiments 

 show, or, if it can be shown, that our spring- water brings out weak or 

 immature fish, then certainly other water should be used, even though 

 the whitefish branch of the work is removed to some other locality, which 

 I shall be perfectly willing to have done. 



We have other water near the hatchery (branch of river Eouge, see 

 map), that is as cold as can be found anywhere during the winter; but 

 it is lower than the hatchery, and would have to be pumped. This would 

 entail some expense, but would give us more water for trout i)uri3oses. 

 We could also, by running varying proportions of si)ring and creek water 

 on different sections of eggs (whitefish), hatch them at will, as wanted 

 for distribution. 



Another good way, too, if it is thought best not to hatch whitefish at 

 Northville in the spring- water, is to put up an inexpensive hatchery 

 adjacent to some good si>awning grounds, as, for instance, at Alpena. 

 At such a point, the hatchery could be filled at a very moderate expense, 

 as every fisherman would lend a hearty co-operation. By using jars 

 only and having no shipments to make, two men could easily care for a 

 very large number of eggs. Enough could be sent on to Northville, say 

 five or ten million, to fill orders from other i^oints, making this head- 

 quarters for shipping, correspondence, &c. 



Our whitefish hatched in from 75 to 90 days this year — an unusually 

 brief period ; but since they are the exact counterparts, both in appear- 

 ance and vigor, of the fish of previous hatchings, I am forced to admit 

 that the opinions I have hitherto held in regard to this matter were 

 erroneous. But I think there is a very good reason why the use of spring- 

 water for hatching these fish should be discontiiuied, unless, indeed, we 

 can devise some means of reducing it to the proper temperature to "keep 

 the fish back" later than this; for, although the "premature" fish are 

 perfectly normal, it is altogether probable that the proper food exists 

 in much greater abundance later on. 



I can but think, too, as Professor Forbes says, substantially, that a 

 great mistake is made in planting the fish in such large numbers in one 

 jdace. The water should be teeming with the aj^propriate food at the 

 time and jdace the fish are set free, to meet the requirements of so vast 

 a number of minnows as are usually released in one place. 



According to Professor Forbes' recent investigations off" Racine, each 

 minnow would have to skirmish around throTigh a vast deal of water to 

 find suificient nourishment, even though he had no comrades with which 

 to divide the spoils. Grown fish might easily migrate to rich feeding- 



