156 American Fisheries Society. 



have the difficulty in winter of ice forming at these obstructions, with the 

 result that many of the fishways are broken up or carried away. 



As to the electrical screens, an electric shock seems to me to be a 

 rather harsh method of driving fish away. It may work all right, but I 

 think the simpler method of a revolving wheel or screen would be satis- 

 factory; it has worked quite well in some of our western waters. I should 

 like to ask Mr. Cobb what kinds of fish he was particularly referring to as 

 making the ascent. 



Mr. J. N. Cobb: I was referring to the chinook salmon, the silver 

 or coho, and the steelhead trout. The red salmon does not run up that 

 stream, nor does the dog salmon or the humpback. I assure Dr. Prince 

 that I do not think the fish suffer from electric shock; it simply causes them 

 to feel a tickling sensation and induces them to move on. We have never 

 seen one killed, because the shock is very slight. Some which were playing 

 around the electrodes were merely knocked senseless. They drifted away, 

 but as soon as they got beyond the influence of the current they revived. 



