TROUT FLY-FISHING IN AMERICA 



occasionally trout are caught having only one good eye, 

 the other one in some way having been injured or lost. 



As between normal eyesight and blindness, the two 

 extreme conditions, coloration is indirectly influenced by 

 sight, but as to the intermediate stages little or no effect is 

 apparently produced as a general proposition ; at all events 

 not as far as I am able to discover. 



The large majority of all trout have normal eyesight, 

 some have one defective eye and a very few are afflicted 

 with partial or complete blindness. Trout that are truly 

 blind, however, are very short-lived, and specimens of 

 such trout are difficult to obtain. They are very short- 

 lived, because it is impossible for them to find sufficient 

 food upon which to exist, and such fish do have dark 

 coloration. 



The dark coloration, however, in my judgment, is not 

 due to loss of sight or blindness, but to other causes, the 

 controlling and primary one being light. 



The blind trout is an "under-surface" feeder, so much 

 so, that it can be properly called a **ground feeder," locat- 

 ing its limited supply of food very largely by the sense of 

 smell. It follows, then, that the blind trout necessarily 

 lives its short life in the deepest water of its habitat, and is 

 poorly nourished. I have found that it is due to these con- 

 ditions that blind trout take on a subdued or dark colora- 

 tion and not to the loss of sight. 



Any abnormal coloration In trout is undoubtedly due 

 to peculiar conditions in each individual case, and they 

 come either from external or internal sources or both, 



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