AKTIFICIAL PROPAGATION OF TROUT. 5 



it is the amount permeating the fish that gives tlie color its intensity. A well- 

 fed, comparatively inactive adult trout will present a more intensive shade of 

 the tlesh than a fish of the same age living in running water, where its live- 

 lihood depends upon its activity, although it may be a well-conditioned, shapely 

 fish. In the latter instance the food has been assimilated and utilized in the 

 development of energy. 



SIZE. 



The size of the brook trout varies in different localities and prob- 

 ably is influenced by the abundance of natural food and the charac- 

 teristics and range of the water in which it is found. A trout will 

 not attain a very large size in a restricted environment no matter 

 how much food it has. The average size, as taken from time to time 

 in any given body of water, is remarkably uniform. It is generally 

 true, and particularly as regards waters of small extent, that the size 

 of the fish decreases in proportion to the numbers occupying a given 

 body of water. Referring again to Kendall's Rangeley Lakes paper, 

 we read on page 550 : 



As previously stated, trout grow faster and larger in the larger bodies of 

 water when food is plentiful than in smaller or more circumscribed places. 

 Given plenty of room and plenty of food, it is a question to what size a trout 

 might not attain. There are at least two natural conditions aside from those 

 of environment just mentioned that probably affect trout. There is, doubt- 

 less, a natural size limit beyond which the trout could not go if it lived to be 

 200 years old; but even if, there wei'e no size limit, the species doubtless has 

 a more or less definite life tenure that would in any case limit its growth. 



The comparatively recent development of the study of scales has shown 

 that rarely, if ever, is a greater age than 10 years attained by European 

 trout {S. fario), and probably not that; the lake trout of Scandinavia prob- 

 ably not over 12 years. 



Allowing, then, an average growth of 1 pound a year, as suggested by Mr. 

 Page's experiment, the record fish would be only 12^ years old. It is quite 

 probable that trout seldom live longer than 12 or 15 years. 



The largest brook trout taken in American waters whose weight 

 has been reliably authenticated was from Rangeley Lakes, Me., 

 its weight being 12^ pounds, while from the Nepigon River, a 

 Canadian tributary of Lake Superior, an example weighing 14J 

 pounds is recorded. From other streams brook trout weighing 10 

 and 11 pounds are recorded, but individuals of these sizes are by no 

 means common. 



The rate of growth also varies with the surrounding conditions, 

 and is more rapid in water having a fairly uniform temperature 

 throughout the year. The most favorable temperature for this 

 fish is from 45 to 65° F. In the waters of the Eocky Mountain States 

 where it has been successfully introduced, the brook trout grows 

 rapidly and attains a large size. At present probably the largest 

 examples are to be found in certain of the natural and artificial lakes 

 of the lower altitudes of Colorado, though in the colder waters of 

 the State, in altitudes ranging above 4,000 to 5,000 feet, it probably 

 does not average more than 6 to 8 inches in length. Under favor- 

 able condititons the average growth is about as follows : 



leches. 



1 year old 4 to 5 



2 years old 7 to 8 



3 years old 10 to 12 



4 years old 14 to 16 



