122 FLY FISHING AND SPINNING 



makes this " sheet bend " absolutely secure, and permits 

 of an attachment which can be instantly released.* 



SEX IN TROUT 



The cock fish may generally be distinguished from the 

 female during the spawning season by the fact that the 

 adipose fin is more developed, thicker and stiffer than in the 

 hen fish. 



During the open season the reader may probably find 

 it difficult to distinguish between the sexes of the trout. 

 As before stated, it is claimed that the cock fish has a longer 

 and stouter adipose fin ; there is a bluntness about the nose 

 and head of a male fish, although this bluntness is lost as the 

 spawning season approaches. At this time the colour 

 becomes more vivid on the sides ; and the belly of the fish, 

 both before and behind the ventral fin, has a decidedly 

 square appearance in the cock fish. The hen fish at this 

 time loses some of her colour, and grows big with spawn, 

 but does not acquire the squareness in the underneath part 

 of its body peculiar to the other sex. 



THE APPEARANCE OF TROUT 



The colour of the trout changes rapidly in relation to its 

 surroundings. If a dark trout be taken from under a bridge 

 or from some deep shady portion of the river, and placed 

 in a shallow enclosure with light-coloured gravel at the 

 bottom, he will, before many hours have elapsed, have 

 changed to a much lighter colour. A trout which inhabits 

 a river one side of which is deep, over-shadowed, and with a 

 dark bottom, will when on that side of the river be possessed 

 of a dark colour ; but if he should during certain hours of 

 the day cross the river and lie on the opposite side in sun- 

 light, on a shallow, gravelly bed, he will rapidly become 

 lighter. 



* For a description of other knots see Chapter XVI. 



