ATTEMPTS TO GUIDE SMALL FISH WITH UMDERWATER SOUND 



One of the most uncertain and difficult problems in providing for 

 the safe passage of migratory fish around high dams is created by the 

 migration of the young salmon to the ocean from upstream spawning 

 grounds. Experiments indicate that turbine and spillway hazards at 

 one dam may cause a considerable loss of these small fish. This loss 

 becomes of increasing concern when multiplied by each new dam under 

 construction or proposed for the Columbia River » Vlhen this potential 

 threat to the resource first became known, the Fish and Wildlife Service 

 initiated studies to develop methods of providing safe downstream 

 passage for fingerlingSo Basic to the accomplishment of this objective 

 is a knowledge of their distribution in the river» 



Research on this problem revealed that fingerlings of chinook 

 salmon ( Oncorhynchus tshaw^'-tscha ) in the Columbia River are found at 

 all depths of the water and from shore to shore in nearly equal numbers. 

 Thus we knew that fish were passing through turbines and spillways in 

 proportion to the amount of water passing through these structures, and 

 it became urgent that we develop methods of diverting the fingerlings 

 into safe channels of migration. The desirability of sound as a means 

 of guiding fish cannot be overlooked, because it does not require the 

 use of structural equipment such as floating booms or screens and because 

 it can be beamed and reflected much like light. 



Through the cooperation of the U. S. Army Corps of Engineers and 

 the U. S. Navy, the Fish and Wildlife Service was given the opportunity 

 to test the effects of underwater sound of various frequencies and 

 amplitude on fish. The tests were made during November and December, 

 I9I7, and March and April, 19^9, at the Biological Station at Leetown, 

 West Virginia. The tests were limited to four undersea warfare sound 

 producing instruments involving three principles of sound production: 

 (1) electro-magnetism, (2) Piezo-electricity and (3) the hydraulic turbine. 

 Because young Pacific salmon were not available at the site, the physio- 

 logically similar rainbow ( Sal mo gairdnerii) and brown (So_ trutta) trouts 

 were used as experimental animals. 



CHARACTERISTICS OF SOUND .^D SOUND DEVICES 



All sounds are the result of physical vibrations. Sound waves in 

 the air are the result of molecules of air being pushed against one 

 another to form compression waves. This distinguishes sound waves 

 from radio, radar, or similar electronic impulses which are the result 

 of xvave motion between the molecules. Sound waves in the water develop 

 when the medium is alternately compressed and expanded mechanically. In 

 either of the two elements, sound waves travel from the source in a pattern 

 sindlar to that obtained by dropping a stone into a quiet pool.i/ 



1/ Actually sound waves expand in all directions from a non-directional 

 source, in a series of concentric spheroids. 



