Natiiral History of the River Trout. 173 



way have migrated there, because in all tidal rivers 

 the lower reaches of the stream consist of neutral 

 water sweet half the day, and brackish the other 

 half. The brown trout which inhabit these reaches 

 would of necessity acquire some of the characters 

 of the sea trout would they not ? and I should 

 not myself consider them to be hybrid, because 

 nature does not make, and therefore as a rule 

 produce, unproductive fish." 



Taking all the various causes for change of 

 colour in the common trout, I can only come to 

 the conclusion that there is only one species of the 

 Salmo fario in Great Britain, and that the so-called 

 species of Couch and other authors are only varieties 

 of this fish. 



What becomes of the trout in winter ? Do they 

 hibernate ? 



Mr. Houghton (loc. cit.), in his paragraph upon 

 " Trout Spawning," makes this remark : " Sterile 

 examples are known to occur, and have frequently 

 been taken. In such cases, the trout are in 

 season in January and February, being excellent 

 food." So Walton says: "So there be some 

 barren trouts that are good in winter; but there 

 are not many that are so." Trout to be excellent 

 food in January and February must have had them- 

 selves excellent food, and where is that to be got 

 in January and February, except in the most open 



