oH SfiVENTH REPORT OF THE FOREST, FISH AND GAME COMMISSION. 



water has reached a temperature of about 40°. After spawning they again retire to 

 deep water where they remain during the winter. Mr. Milner observed that the 

 shoreward migration varies with locality and is influenced also by depth of water 

 and temperature. In Lake Erie, for example, which has a high summer tempera- 

 ture, there is no shoreward migration in summer. It is noted also that the White- 

 fish moves along the shore and in some cases it ascends rivers for the purpose of 

 spawning. It is believed also that when the feeding grounds of the Whitefish are 

 polluted b\- mud the fish temporarily seek other localities. There appears to be a 

 spring and summer migration likewise from lake to lake. Spawning takes place 

 during October, November and December on shoals or occasionally in rivers. The 

 female is larger than the male. According to the observations of George Clarke, 

 the two sexes in the act of spawning frequently throw themselves together above 

 the surface, emitting the spawn or milt with the vents close together. Spawning 

 operations are most active in the evening, are continued at night and the eggs are 

 deposited in lots of several hundred at a time. The number of eggs in a fish of 7^^ 

 pounds was 66,606; the average number being nearly 10,000 for each pound of the 

 female's weight. The period of incubation depends on the temperature. The 

 usual time of distribution of the young is in March and April. The very young 

 are described as swimming near the surface and not in schools. They are very 

 active and soon seek deep water to escape from their enemies. Their food consists 

 chiefly of small crustaceans. The adults subsist on the same food with the addition 

 of small mollusks. 



The only means of determining the rate of growth of the Whitefish is by arti- 

 ficial rearing. Samuel Wilmot had young fish which were 5 inches long at the age 

 of four months. The growth under natural conditions must be even greater than 

 this. Mr. Wilmot has seen Whitefish measuring 7 inches in December in his ponds. 



The eggs of the Whitefish are destroyed in immense numbers by the Lake Her- 

 ring, Argyrosoinus artcdi. The water lizard, Menobranchus, also consumes vast 

 numbers of the eggs. The young Whitefish are eaten extensively by the Pikeperch, 

 Black Bass, Pike, Pickerel and fresh-water Ling. The Lake Trout also feed on the 

 Whitefish. A leech parasitic of the Whitefish proves very troublesome to that 

 species, and the scales are liable to a peculiar roughness which has been observed 

 late in November or during the spawning season. There is also a lernean which 

 fastens itself to the gills and other parts of the Whitefish. 



The excellence of the flesh of the Whitefish is so well known as scarcely to 

 require mention. Its commercial value is great. In Lake Erie in 1885, according 

 to statistics collected by the U. S. Fish Commission, 3,500,000 pounds of Whitefish 



