A PLAN FOR PROMOTING THE WHITEFISH PRODUCTION 
OF THE GREAT LAKES. 
a 
By PAUL REIGHARD, 
University of Michigan, Ann Arbor, Mich. 
ad 
APPROACH TO THE PROBLEM. 
In attempting to devise a plan for the promotion of the whitefish produc- 
tion of the Great Lakes it appears that certain avenues of approach available in 
the case of cognate problems are in this case closed. This will perhaps become 
clear if we first consider the possible modes of accomplishing the purpose. 
The procedures that suggest themselves are those which might be followed in 
any like problem, and may be conveniently grouped in the following way: 
Preservative measures: : 
1. Prevention of the water pollution which may occur through the 
agency of sewage, garbage dumps, sawdust or other manufacturing 
refuse, cinders, ashes, and other refuse from steamers and other 
boats. 
2. Restriction of fishing operations (limitations on fishing season and 
on character and number of nets to be used). 
Restorative measures: 
3. Distribution of fry. 
4. Introduction of improved races of whitefish. 
5. Increase of the food of the whitefish. 
Experiments on the effect of water pollution on fish have been conducted 
abroad and are summarized by Professor Prince (1900). The investigations 
carried out for the Canadian government by Mr. Knight (1901 and 1907) on the 
effect upon fish of the pollution of Canadian streams by the refuse of sawmills, 
pulp mills, gas works, and nail mills are noteworthy, but do not appear to have 
any application to the Great Lakes. In this country we appear to have no simi- 
lar published investigation, so that we have no means of knowing the extent of 
water pollution in the Great Lakes or its effect on the whitefish. We are 
therefore compelled in this paper to disregard a possible means of increasing the 
whitefish production through the prevention of water pollution. 
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