The Salmon 



147 



to die, and continue to drop off until the end of the spawning 

 season, when nearly all die. So infectious is the disease that three 

 years ago on the river 

 Almond about a hundred 

 fish died per day in a dis- 

 tance of less than a mile. 

 Whenever there was a slight 

 flood in the river large num- 

 bers of fish without a spot 

 on them ascended, and in 

 the course of a few days 

 nearly all became affected 

 and died (Fig. 146). One 

 or two white spots appear 

 on the head or the dor- 

 sal fin. These are at 

 first very small, but in two 

 or three days the disease 

 spreads rapidly. The fish 

 jumps frequently, as if to 

 try to rid itself of it, but 

 soon becomes exhausted 

 and dies. Autumn fish 

 appear better able to with- 

 stand the disease than 

 spring fish just from the sea, 

 for a spring fish will often 

 die with only one spot 

 on its head no larger than 

 a shilling, while an autumn 

 fish will live although its 

 body is almost entirely covered. The disease takes the greatest 

 hold when a fish is about to spawn, more especially if the weather 

 be cold, and many hundreds fall victims to its ravages. The accounts 



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