As there were obvious differences in the sound test distributions 

 and the control distributions it seemed desirable to apply contingency- 

 tests to the results to determine if the differences were significant. 

 In all cases (comparison of sound tests and controls of the same dxara- 

 tion of time) the results were highly significant, thus indicating a 

 marked difference between the sound tests and comparable controls., 



This significant difference, however, can not and should not be 

 interoreted as evidence that sound waves either attracted or repelled 

 the fisho There is nothing to suggest that the sound waves produced 

 by this apparatus had any influence on the distributions. 



For practical manipulation of sound waves for leading and guiding 

 fish into safe passages around dams and other stream barriers, it is 

 necessary to have a stimulus which is very close to 100 percent 

 efficient „ None of the sounds produced by this first sound producing 

 equipment showed results which in any way approach this efficiency. In 

 no instance did the "water hammer" show a definite attracting or repel- 

 ling effect on the fish during any of the tests. 



PIEZO-ELECTRIC CRYSTAL TRANSDUCER HIGH FREQUENCY 



On December l5, Mr. D. W. Beecher of the Naval Ordnance Laboratory 

 assembled high frequency equipment for our use at Leetown. The oscillo- 

 scope and signal generator for frequencies of 12 kc to 70 kc were con= 

 nected to the amplifiers used for the low frequency tests. The trans- 

 ducer was a four-inch brass cylinder containing quartz crystals and 

 caster oil, covered with a rubber diaphragmo The crystals changed 

 dimensions when subjected to a high frequency, alternating current The 

 entire unit, a little over 8 inches in length, weighed approximately 

 five pounds. The speaker could be beamed much like a flashlight and 

 had approximately a 6o* cone of divergence. The projector may be de- 

 scribed as having the following characteristics: At frequencies of 12 

 kc to 6o kc - U,000 dynes/cm^ or 72 db above 1 dyne/cm^ at 3 feet, 

 except for 10 db dips at each end and at approximately 35 kc. 



For the first tests the transducer was beamed directly upon the 

 fish in section no. 1 in an attempt to frighten them out. Tests na' s 

 hi and U8 (Figure l6) show that the fish moved even faster vihen the 

 sound was not on^ Test no. h9 appeared conclusive. The sound was 

 turned on and all fish moved away from the transducer. The optimism 

 was short-lived when in test no. 50, a control, the fish moved in a 

 similar pattern in nearly identical numbers. This frequency (50 kc) 

 was tried again and again informally, without results which could be 

 assessed as conclusive. 



Any frequency which elicited even a suggestion of a response, was 

 repeated informally. The equipment was given a series of tests utiliz- 



18 



