226 REPORT OF THE COMMISSIONERS OF 



Practical Efforts at Extermination. 



When the full life history of any animal is as well known as is that of the lamprey, 

 as given above, mankind is in position to take practical measures for either its cultiva- 

 tion or repression. There is no animal or plant that cannot be made to either increase 

 or decrease by the intelligent effort of man. Each has its weak point at which it must 

 be assailed to exterminate it, or during which time it should be given especial help or 

 protection to lead to its increase. However, if this vital period is not known, it is 

 impossible to suggest practical measures that will prove effective. Hence, to make 

 fishes more abundant in our State, it is essential that we should have greater 

 knowledge not only of them, but also of all their enemies. 



Practical fish farming is the most neglected of all possible important industries of 

 man, and there is no single jurisdiction on earth that is as well provided by Nature 

 for the development of this promising resource as is the State of New York, with all 

 her many fine bodies of pure and fresh water. Yet it is unfortunate that little besides 

 the so-called " fish culture " of hatcheries and the planting of young has been done in 

 this State. Illinois, Indiana, and other western States are leading at present in 

 practical investigations along this line. Notwithstanding the good work of several 

 hatcheries, we cannot expect to have fish abundant in this State while the young that 

 are thus produced are turned loose to starve in barren waters, where intelligent efforts 

 might make their food abundant, and while the nature of the food and needs of the 

 young fish are not known, and while in the waters there remain to multiply unmolested 

 such serious enemies of our best fish as we have just shown the lampreys to be. 



No person who has any knowledge of this subject realizes this more fully than 

 does Hon. A. N. Cheney, the able State Fish Culturist of the State of New York, and 

 it is due to his efforts, combined with those of the writer and other interested persons 

 at Cornell University, and especially Senator E. C. Stewart, that an item was inserted 

 in the Annual Supply Bill, in the spring of 1897, providing $500 "to be expended by 

 the New York State Fish, Game and Forest Commission for the extermination of 

 lampreys and noxious fishes of Cayuga Lake, and investigations of fishes by the 

 Biological Department of Cornell University." As Fellow in Vertebrate Zoology and 

 Teacher of Systematic and Economic Vertebrate Zoology in Cornell University, the 

 writer was given entire charge of the experiments and investigations, without pay, but 

 with two paid assistants. The appropriation was made too late in the spring of 1897 

 to permit the work being undertaken that year, but plans were made for beginning 

 the work early the next spring. 



In considering the known life cycle of the lamprey, it can be seen that its weakest 

 point for attack is when it exposes itself at the spawning season. But to exterminate 



