FOR PLEASURE AND PROFIT. 95 



In its native home, which extends from California, near the 

 Mexican boundary, to Southern Alaska, the rainbow trout 

 (Salmo irideus) is found to thrive in ai wider range of tempera- 

 ture than any other of the Salmonidae. The habitat of the 

 fish is by no means limited to slow, deep, and warm-running 

 rivers, although it seems to " do " better in this country in 

 such. It is this adaptability to a high or low temperature of 

 water that has made the planting of rainbows in this country 

 not only possible but actually profitable from a fish-farming 

 as well as a sporting point of view. And it is the fact that 

 they will stand a much higher temperature than the brown 

 trout that has made it possible to stock with rainbow trout 

 where the introduction of brown trout is impossible. In big 

 rivers and lakes they do well side by side with Fario, and, in 

 the case of really big waters, I see no objection to their intro- 

 duction. By a big river I mean such as the Thames, the 

 Trent, or tlie Lea. They would certainty thrive in such rivers 

 as the Itchen, the Test, the Darenth, the Derwent, the Coquet, 

 and other similar waters, but only at the expense of Fario, 

 and, therefore, their introduction to such waters would be 

 unwise. Lakes and reservoirs certainly profit from their in- 

 troduction, especially where the former have feeders up which 

 the fish can mount at spawning time ; or redds can be made 

 after the manner I have already described. Rainbows are 

 easily reared, and, granted two conditions first, plenty of 

 food ; secondly, plenty of shade they well repay culti- 

 vation. The conditio'n of shade may arise from depth of 

 water, or from trees or aquatic plants ; but it is most impor- 

 tant that it should exist, otherwise ophthalmic troubles occur ^ 

 with the result that the fish have trouble in finding their food,, 

 and, consequently, fall off in condition very rapidly. Rain- 

 bows hold their own in coarse-fish waters containing pike and 

 perch, but under these circumstances it is advisable they 

 should have plenty of range. Where waters communicate 

 with the sea, rainbows will migrate, but, apparently, only 

 when a lack of food occurs in the waters in which they are 

 introduced. For my own part, I cannot see any particular 



