*i 



If 



e 



22 



•>,' 



24 



Figure 11. --Distribution of fish in pens, experiments 19-24. Experiments 19, 20 and 24 started with 1,000 fish 

 in pen No, 1 (far left); 21 started with 1,050 fish in pen No. 1, others as indicated. In controls, gates between 

 pens were raised for indicated period, then lowered. Procedure same in tests, except sounds of Indicated 

 frequency (cycles per second) and duration applied at indicated location while gates up. Numbers and dark 

 bars show distribution of fish after gates lowered. 



10 



