352 BULLETIN' OF THE UNITED STATES FISH COMMISSION. 



two months old will clean out a tank containing a thousand whitefish 

 of the same age in an incredibly short time, simply by picking them off 

 like particles or small shreds of liver on which they are usually fed. 

 But these same whitefish are perfectly safe in the presence of trout 3 

 or 4 5 ears old — they are too small to be noticed. Experiments demon- 

 strating these facts have been tried repeatedly at the Xorthville 

 Hatchery. 



Every trout breeder well understands that food for pond fish should 

 not be too minutely subdivided, as pieces much larger than whitefish 

 minnows go unnoticed by the fish, and, subsiding to the bottom, foul the 

 ponds. It is well understood, even by the barefooted boy, that the mor- 

 sel of bait with which he would entice our small native fishes from their 

 haunts must not be too insignificant. 



We do not know what success one might have in angling for saugers 

 with whitefish minnows as bait, but 1 venture to say that a thousand 

 hooks bated with these minnows, and each manipulated by an expert 

 angler, would fail to secure a score of fish a day, even though a dozen 

 minnows were used at a single baiting. Angling for saugers, either for 

 pleasure or profit, with particles of bait no larger than the whitefish are 

 for six weeks after leaving our hatcheries, would be attended with such 

 meager results that it would speedily cease. 



We are aware that it is freely maintained that, to secure the best 

 possible results, all minnows should be released near the natural spawn- 

 ing beds of their species, so that they might have at least an equal 

 chance with the indigenous minnows. This theory sounds plausible 

 enough, but it remains to be shown that such localities possess any spe- 

 cial advantages for minnow life. The conditions necessary to the exist- 

 ence of embryos and minnows are entirely different. Now, it would be 

 absurd to claim that the honey-combed rocks and reefs always selected 

 by the coregoni for spawning beds are in any way connected with the 

 necessities of the minnows ; and yet it is absolutely necessary, if the 

 species is to be perpetuated in a state of nature, that the eggs should 

 be deposited on beds of this character; since, in view of the long period 

 of incubation, and the rapid development and insidious nature of 

 conferva, they must all perish but for the complete isolation the nu- 

 merous cells of these rocks and reefs afford. As the minnows are no 

 better provided for at such points than elsewhere, it is evident that 

 nature directs the parent fish to select spawning beds wholly with ref- 

 erence to the demands of the embryos. The absence of appropriate beds 

 is doubtless the missing link in the chaiu of conditions necessary to per- 

 petuate the species in many of our small inland waters where all the 

 other links are present. 



NoiiTnviLLE, Mich., April, 1883. 



