NATURAL HISTORY, TORONTO REGION 
in it. Commercially, however, it is of great impor- 
tance, being always in demand and furnishing an 
excellent article of food. 
29. Brook Trout. Salvelinus fontinalis (Mitch- 
ill).—Brook Trout were formerly abundant in all 
the spring streams near Toronto, but of late years, 
owing to the pollution of the water and incessant 
fishing, they have become nearly exterminated. The 
size attained by this fish depends largely upon its 
habitat and food. In small streams it may mature 
at a length of six or eight inches and a weight of only 
a few ounces, while in large bodies of water, with an 
abundant food supply, they will reach eighteen inches 
or more in length and a weight of from six to eight 
pounds. In the cool days of late autumn the Brook 
Trout run up to the headwaters of the streams, and 
there, on the gravelly shallows, deposit their ova; 
the spawning season extending from September in 
the north to December in the south. The number 
of eggs produced depends upon the age and size of 
the fish. Yearlings (that is, fish in their second 
year) will produce from fifty to two hundred and 
fifty ova, while a large fish may produce as many as 
fifteen hundred. The eggs are about three-sixteenths 
of an inch in diameter and of a warm orange colour. 
The period of hatching depends upon the tempera- 
ture of the water, ranging from thirty-two days in 
water at 54° to one hundred and sixty-five days in 
water at 87°. In the early parts of the summer 
Trout frequent the ripples and shallower parts of 
262 
