THE WHITEFISH PRODUCTION OF THE GREAT LAKES. 671 
part of the lake and continuous in a nearly separate area for the western part 
of the lake. Any plants therefore on either side of the lake might well produce 
fish that would make their way to the opposite shore. In interpreting table 14 
it is therefore to be taken into account that the plant affecting the Canadian 
catch is probably much greater than that entered in the table and would prob- 
ably be more correctly represented by values similar to those entered in table 18. 
On the other hand, both the actual and the effective plants in Lake Ontario are 
very much less than in Lake Erie. We see thus in the Canadian waters of Lake 
Erie a very great increase in the production of whitefish correlated with very 
large plants of fry. In Lake Ontario we see a reduction in whitefish production 
correlated with a moderate plant of fry, a plant which is, for unit area, about 
half that of the Michigan waters of Lake Superior for the same periods. 
Restricted areas of Lake Michigan.—In tables 15 and 16 there are brought 
together the data of catch, plant, and nets used in certain restricted areas of 
Lake Michigan. The data for the catch are all taken from the records of the 
Michigan Fish Commission, while those of the plant are published in the reports 
of the Michigan Fish Commission and the United States Bureau of Fisheries. 
The areas selected are as follows: 
(1) An area designated in table 15 as the “north shore’’ of Lake Mich- 
igan comprises the whitefish grounds from the Strait of Mackinaw westward to 
the Michigan-Wisconsin boundary in Lake Michigan. ‘The eastern limit of this 
area is therefore well defined, but at its western limit it is broadly continuous with 
the waters of the State of Wisconsin. It contains 800 square miles, as shown on 
the map of Lake Michigan. The plant of whitefish fry in this area in the three 
successive five-year periods has been from 7,000 to 9,000 per square mile and 
from 5 tog per pound of fish caught. At the same time the catch in round 
numbers has been, in successive periods, 800,000, 950,000, 1,200,000. Here we 
have again a greatly increased catch correlated with a large and intensive plant. 
(2) An area designated in the table as the ‘‘southeast” Michigan shore, 
comprises the whitefish grounds from Little Point Au Sable south to the Indiana- 
Michigan boundary. At its northern limit this area is nearly separated from 
the whitefish area to the north of it, but at its southern end it is broadly contin- 
uous with the Indiana waters of Lake Michigan. These waters, have, however, 
for a long time yielded very few whitefish, so that the area in question may 
be regarded as practically limited by barren waters at its lower end. Its area 
is 300 square miles. For the first period this area received a plant of 22,000 
fry annually per square mile, an average of 125 per pound of fish caught. In 
the second period the plant was reduced to an average of about 7,000 annually, 
or 68 per pound of fish caught. The latter averages are based on a total which 
includes a plant of 4,000,000 made in rgo1 at Michigan City, Ind., just beyond the 
Michigan border. If this plant be excluded the figures for the second period are 
reduced 40 per cent. Here again we have a very large increase in the catch 
