ELECTRIC FISH SCREEN 



12B 



2. When voltage gradients above the paralysis values are applied to fish, the 

 mortality increases with increased time of appUcation. 



3. Fish subjected to electric shocks in various degrees, if not killed outright, 

 quickly recover and do not suffer any serious after effects. 



FlQ. 19 



4. The resistivity of the water in which fish are immersed has an important 

 influence upon the voltage gradient required to produce paralysis, as shown by the 

 values of the water-resistivity correction factor, "W" in Table 4. 



5. Very large variations are found in the resistivity of the water from various 

 streams. The largest fresh-water variation found was one river water that had a 



