BULLETIN OF THE UNITED STATES FISH COMMISSION. 371 



natural food of the trout, in sufficient numbers to sustain a great many 

 fish without the aid of artificial food. 



A comparative statement in figures will better illustrate the future 

 possible trout work of this station. The extension of facilities to the 

 limit of the present water-power of the station will show an aggregate 

 pond area of 10,403 square feet, which will contain a sufficient stock of 

 parent fish (together with the requisite number of growing fish to keep 

 the stock good) to yield an annual income of 1,500,000 eggs of either the 

 Salvelinus fontinalis or Sahno iridea. The acquisition of sufficient basin 

 of the adjacent stream for pond-room and for control of three-quarters of 

 a mile of the channel bed will swell the aggregate pond area to about 

 140,000 square feet. This, with the stream itself, will carry a maximum 

 of stock, at the minimum of cost, sufficient to yield annually 12,000,000 

 eggs. These figures may be regarded as an under rather than an over 

 estimate, since they are made up from the standpoint of our present 

 methods of rearing and handling fish, which experience and experiment 

 are constantly improving. 



We now have on hand in the ponds of the hatchery — 



Brook trout : 



Fry 8, 000 



One year old 1,200 



Two years old 850 



Three and four years old . 400 



California trout : 



Fry 10, 000 



One year old 200 



Two years old 700 



Three and four years old 20 



Land-locked salmon of last spring's hatching 500 



Lake trout of last spring's hatching 300 



Below is a statement of the whole number of fertilized eggs placed in 

 the North ville and Alpena hatcheries to date, including the prospective 

 supply of eggs of California trout for the current season : 



Whitefish (Coregonus clupeiformis) 120, 580, 000 



Lake trout (Cristivomer namaycush) 510, 000 



Brook trout {Salvelinus fontinalis) 1, 050, 000 



California salmon ( Oncorhynchus quinnat) 1, 788, 000 



California trout (Sahno iridea) 283, 000 



Land-locked salmon (Sahno salar; var. sebago) 125, 000 



Wall-eyed pike (Stizostedium americanum) 25, 000 



Grayling ( Thymallus tricolor) 2, 000 



