148 



The Salmon 



, 



of the number of dead diseased fish in different rivers that one 



frequently reads, do not 

 give an adequate idea of the 

 numbers that die, for when a 

 flood comes it sweeps them 

 down in thousands, and they 

 are carried out to sea or 

 left in the estuaries, and 

 perhaps not one in fifty is 

 noticed. All the season 

 through diseased fish drop 

 back daily, many of them 

 reaching the salt water 

 alive. As long as the 

 river continues low many 

 can remain in it, but 

 when a flood comes they 

 are unable to resist the 

 strength of the current. 

 Whenever they lose con- 

 trol of themselves they roll 

 over and very soon die. 

 If the disease died with 

 them it would not be so 

 serious, but weeks after 

 death the disease continues 

 to develop, until every part 

 of the fish is covered to the 

 depth of a quarter of an 

 inch. In Fig. 149 I have 

 scraped away a part to show 

 the thickness of the fungus. 

 In order to prove that fungus attacks dead fish, I tied a clean fish 

 without a spot on it to a stake in the river and left it there for a fort- 



FIG. 149. Showing fungus developed after the fish was dead 

 for a considerable time. See two parts scraped off. 



