BULLETIN OF THE UNITED STATES FISH COMMISSION. 351 



tion ; so that but a very small percentage of the eggs deposited by the 

 parent fish bring forth living minnows. 



Nature has also accorded a very frail and feeble existence to the in- 

 fancy of whitefish life. It would hardly seem possible that a single 

 minnow could survive this period, were they pursued as prey by the 

 thousands of predaceous fishes with which they must mingle upon rising 

 from the spawning beds. Indeed, it may be stated without fear of suc- 

 cessful contradiction that not only the whitefish minnows but those of 

 many other species would be speedily sacrificed to predaceous and can- 

 nibalistic tendencies, were there no compensating conditions coexistent 

 with that apparently defenseless period of their existence. But nature, 

 in her economy, appears to strive to guard against extinction. Thus, 

 it is said that certain defenseless species have the power of vision devel 

 oped to that degree that they are enabled, with due vigilance, to keep 

 a safe distance betweeu themselves and their rapacious but short-sighted 

 enemies; that others are so identified in color and appearance with the 

 waters they inhabit as to be scarcely discernible; and that others still 

 are so surrounded with iucidental protective agencies that they enjoy 

 some degree of immunity from the ravages of predaceous species. Of 

 course the circumstances which afford protection in one case may be 

 entirely inoperative to protect fish at another stage of development or 

 belonging to another species. Minnow life may emerge unharmed from 

 surroundings that would insure total destruction to the same individuals 

 at later stages of maturity. Thus, the frailty and insignificance of white- 

 fish minnows are, of themselves, ample safeguards against destruction 

 by the larger deep-water fishes with which they instinctively seek to 

 associate from the moment they are released from their shell inclosures 

 For several weeks tbey aie so minute, to say nothing of their being 

 nearly transparent and invisible, as to render it quite unlikely that they 

 are preyed upon by anything within the range of deep-water fishes. 

 Doubtless there is some loss by starvation, and some are strained out 

 by gill-rakers, along with fish-food collected in this way. Such losses, 

 however, are merely incidental. 



These same minnows would doubtless be destroyed by the "chubs" 

 and "shiners" that swarm inshore by the thousands, evidently to keep 

 out of the way of the larger rapacious fishes. But from actual observa- 

 tion I am able to say that the whitefish minnows invariably go to deep 

 waiter when planted in shoal places. In such cases they settle towards 

 the bottom, heading to deep water, and soon pass out of sight. 1 have 

 noticed also that when deposited in deep water they do not remain at 

 the surface, but almost immediately work down out of sight. 



We grant that the sauger is not a large fish; but obviously it is too 

 large to pay any attention to the minute whitefish minnow. It is very 

 doubtful if even the fry of brook trout would be molested by the saugers, 

 and yet the relative size of trout and whitefish fry is such that the lat- 

 ter speedily disappear in the presence of the former. A dozen trout 



