Figure 12. Distribution of fish in pens, experiments 25-30. All experiments 

 started with 1,000 fish in pen No. 1 (far left). In controls, ^ates between 

 pens lifted for indicated period, then lowered. Procedure same in tests, 

 except sounds of indicated duration and frequency (cycles per second) applied 

 at indicated location while ^ates up. Numbers and dark bars Indicate distri- 

 bution of fish after gates lowered. 



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