THE WHITEFISH PRODUCTION OF THE GREAT LAKES. 681 
lessen the cost of fishing. The conclusion reached in this section is that neither 
the close season nor regulation of the amount of apparatus is in itself sufficient 
to increase the output of the whitefish fisheries of the Great Lakes. The close 
season is presumably of assistance and should be preserved, since it protects 
the fish when they may be most readily taken in large numbers. The regulation 
of the length of apparatus to be employed in the whitefish fisheries has not 
resulted in preserving the fisheries, but is presumably advantageous in lessening 
the cost of operation, since it increases the number of pounds of fish taken per 
unit of net without reducing the total catch. 
SUMMARY OF CONCLUSIONS. ° 
1. The possible modes of increasing the production of whitefish in the 
Great Lakes are discussed and the conclusion reached that under existing con- 
ditions there are but two modes available, planting of whitefish fry and restrict- 
ive legislation. The problem is then stated to be a statistical one, that of deter- 
mining by the study of existing statistical data the effect on the whitefish catch 
of the lakes of the planting of whitefish fry and of various forms of restrictive 
legislation. It is shown that it is necessary to have statistics for a continuous 
period of years for true whitefish only both for plant and catch and under various 
legislative restrictions. The necessity of discussing average catches with refer- 
ence to unit areas of fishing ground is insisted on. Finally, it is shown that 
the necessary statistics are to be found only in the records of the Michigan 
Fish Commission and in those of the Department of Marine and Fisheries of the 
Dominion of Canada. 
2. The habits of the whitefish are discussed, with the conclusion that the 
fish is a bottom feeder, restricted in its range during nine months of the year to 
waters of very definite depth. The depths assigned by investigators to the white- 
fish are then tabulated for each of the Great Lakes, the areas showing these depths 
are charted, and the extent of these areas measured in square miles. The 
whitefish areas as thus defined are then briefly described for each lake and it is 
shown that they are not in all cases continuous areas. Evidence is then adduced 
to show that the whitefish are local in their habits, so that each part of each 
area supports its own group of fish, which are in large measure confined to the 
area, leaving it only in fall when going inshore to spawn and in spring or sum- 
mer for about two months. 
3. In studying the relation of the plant of whitefish fry to the catch it is 
found that in those lakes or parts of lakes where there has been a large and 
intensive plant of whitefish fry (30,000 per square mile) there has been a corre- 
lated increase in the catch of whitefish (72 per cent); in those lakes or parts of 
lakes in which there has been a moderate plant of whitefish fry (10,000 per 
square mile) there has been a slight increase in the catch of whitefish or the 
