The Salmon 



55 



ing upstream all the time. If the gravel is easy to work, the spawning- 

 bed thus scooped out is often a foot deep ; and by the time spawning 

 is completed the fish will have turned up the gravel to the extent of 

 2 to 3 yards upstream, and about 2 feet across stream (Fig. 45). The 

 spawning-beds can always be detected by observing the light colour 

 ot the gravel which has been newly exposed, contrasted against the 



¥\c 47. — Shi'winn; Salmon-Beds diverting the water where the gra\'el is raised, 

 River Duart More, Sutherland. 



darker-coloured part on each side (Fig. 46). The whole process of 

 depositing the spawn in the gravel to the depth of 10 or i 2 inches occupies 

 from three to fourteen days, according to the state of the weather and 

 the water. So eager are fish to spawn in their own river that I have 

 observed them begin five minutes after they entered. If, on the other 

 hand, they are prevented from spawning by being delayed in pools 

 during low water, they retain their spawn for weeks longer than they 

 would have done had the water been suitable for their reaching the 



