660 BULLETIN OF THE BUREAU OF FISHERIES. 
strengthens this conclusion when he finds that on grounds where whitefish were 
formerly abundant, but on which they are now scarce, the food of the whitefish 
still exists in apparent abundance. The following quotations from Professor 
Ward are of interest in this connection. He says (p. 24): 
We are thus forced to the conclusion that the decrease in the whitefish supply can 
have no other cause than overcatching. This is not the place to discuss good and bad 
methods of fishing or remedies for the trouble. Our investigations point unmistakably 
to the cause of the depletion in the whitefish supply; it is the removal from the lakes 
of a larger number than can be replaced by natural processes and than has been success- 
fully returned by artificial hatching. 
Fic. 5—LAKE ONTARIO. 
Whitefish area (shown in black), ro to 20 fathoms. (Reduced from U. S. Hydrographic Office chart no. 1477. Scale: 
rin. =about 48 miles.) 
Again (p. 67) he says: 
There is a plentiful supply of whitefish food on the old fishing grounds. No reason 
can be assigned for the diminution in the supply of whitefish save overcatching. 
I can only concur in these opinions, which are supported by incontro- 
vertible evidence collected by many investigators. 
EFFECT OF PROPAGATION UPON WHITEFISH PRODUCTION IN THE GREAT LAKES. 
ANNUAL CATCH AND PLANT IN MICHIGAN AND CANADIAN WATERS. 
In tables 1 to 10 are arranged certain data concerning the annual 
catch and annual plant of whitefish in Michigan and Canadian waters of the 
Great Lakes for the fifteen years 1892 to 1906, inclusive. The catch of whitefish 
