LOW FREQUENCY TRANSDUCER 

 "WATER HAMMER" 



10 MIN. CONTROL 



90 MIN. CONTROL 



313 



12 



52 



68 



67 



78 



117 



104 



49 



95 



16 HOUR CONTROL (OVERNIGHT) 



HO 

 _ 



44 



34 



13 



58 



Figure 8. --Distribution of fish in pens, experiments 1-6. There were 100 fish in each pen at the beginning 

 of each experiment. In controls, gates between pens were lifted for periods indicated, then lowered. Tests 

 differ only in that sounds of indicated frequencies (cycles per second) and durations were applied at indicated 

 location while gates up. Numbers and dark bars indicate number of fish in each pen after gates lowered. 



