ELECTRIC FISH SCREEN 



105 



the direct control of the sympathetic nervous system and hence are disturbed very 

 seriously by a severe electric shock. The first indication of recovery after the 

 potential is removed is a reestablishment of gill action, or a strengthening of it if the 

 gill action has not stopped entirely. After the gill action has reached nearly normal 

 the body begins to flex, and in a short time the normal swimming position is resumed. 



Fia. 6 



The movements are slow and sluggish at first, but, except in the most severe cases, 

 normal activity is resumed quickly. This recovery from electric shock requires 

 varying amounts of time from a few seconds to 45 or more minutes. The longest 

 time of recovery accurately recorded during the tests was 45 minutes for a 7-inch 

 rainbow trout. 



