42 Tivciity-sez'ciitli Annual Meeting 



sphere. If the magnitude of the effort be surprising", its results, or 

 lack of results, is rather startling. 



To illustrate, it will only be necessary to mention a few well- 

 known varieties, beginning with the broek trout, whose habitat 

 is perhaps most isolated — that is, fontinalis has fewer coinhabi- 

 tants of his domain than do other species inhabiting larger bodies ^ 

 of water, and in consequence fewer obstacles to reproduction are 

 present. 



In harmon^■ with its environment, the parent fish is required 

 to make but a moderate effort at procreation, spawning an aver- 

 age of about 800 eggs yearly as a guaranty of the perpetuation of 

 her kind; while the lake trout, whose neighbors are legion, de- 

 posits an average of 10,000 ova, showing that the namaycush 

 contends vv^ith greater odds. Again, whitefish, of the same genus, 

 living under somewhat similar conditions as the lake trout, are 

 far more prolific in ova, contributing an average of 28,000 eggs 

 annually in her procreative efforts, demonstrating that the species 

 is surrounded, or subject, to still more unfavorable conditions. 

 The sturgeon, representing another g'enus, deposits about 200,000 

 ova, while the ling stakes 800,000 eggs that she will inure a pos- 

 terity. 



Notwithstanding this prolificness of ova in these varieties, the 

 net increase is phenominally small, the decimal .002 with brook 

 trout and .000002 in case of the ling would prol:)ably more than 

 cover the actual net yearly increae, under strictly normal condi- 

 tions. It would be impossible to enumerate the different agents of 

 destruction causing such enormous waste; the principal reason, 

 however, is well known to students of nature. Nearly or quite 

 all varieties of fishes are spawn eaters, that is, ova deposited by 

 one species is eagerly sought and devoured by another, the 

 spawning ground of a class becoming in turn feeding grounds for 

 representatives of a dift'erent species. 



Obviously, depletion of a certain species without a correspond- 

 ing reduction in numbers of its coinhabitants, would seriously re- 

 tard nature's recuperative efforts in behalf of the partially ex- 

 terminated class, as "balance" would be destroyed and umiatural 

 conditions prevail. 



As instances of rapid depopulation of virgin waters may be 

 cited two of Michigan's most magnificent streams, the Au Sable 

 and Manistee Rivers. Through a long residence near the head 

 waters of both these streams, whose sources may be compassed in 

 a three-mile walk, I became familiar with their early history. 



In 1872 their banks were in a primitive state, their waters 



