reactions of salmon fingerlings to water 

 currents. Water flow serves to guide and 

 transport fish in the river as they migrate 

 from the hatching area to the sea. The 

 orientation of fingerling salmon to the 

 water flow, their upstream or downstream 

 movements, variables such as changes in 

 water temperature, light intensities, cUid 

 dissolved gas tensions, the age of the fish, 

 and the season of the year are all to be 

 studied for their possible role in the up- 

 stream or downstream movement of finger- 

 1 ings . 



In conjunction with the rheotsixis 

 study we are conducting tests to determine 

 the factors which affect fingerling swim- 

 ming ability. A knowledge of physical 

 abilities and factors that govern perform- 

 ance is necessary for proper evaluation of 

 rheotactic responses. Preliminary tests 

 have emphcisized the importance of the rela- 

 tion of water temperature to swimming 

 jibility . 



Studies of the behavior of fingerlings 

 in an electrical field at present are con- 

 cerned with minimum voltage-gradients at 

 which fingerlings respond. Information on 

 threshold gradients is needed to facilitate 

 both the design of electrode array installa- 

 tions and the placement of nonelectrif led 

 bypasses. 



Group behavior of salmon fingerlings 

 is also being studied. Differences in 

 behavior of sockeye salmon smolts have been 

 found in the laboratory to be related to 

 numbers of fish and spatial relationships. 

 Laboratory observations indicate that silver 

 salmon smolts have a very different behav- 

 ior pattern from sockeye smolts. Group 

 behavior in restricted spaces may be of 

 considerable importance in the design of 

 fingerling bypasses and traps. 



These and other studies performed by 

 the staff of this laboratory are part of a 

 larger fish behavior research program. Its 

 purpose is to obtain detailed information 

 on migratory behavior of juvenile and adult 

 fish necessary to the design of effective 

 facilities for fish passage. 



LITERATURE CITED 



DUNCAN, REA E. 



1956. Use of infrared radiation in the 

 study of fish behavior. U. S. 

 Fish and Wildlife Service, Special 

 Scientific Report — Fisheries No. 

 170. 16 p. 9 figs., 2 tables. 



MOORE, HARVEY L. , AND H. WILLIAM NEWMAN 

 1956. Effects of sound waves on young 



salmon. U. S. Fish and Wildlife 

 Service, Special Scientific 

 Report—Fisheries No. 172. 19 p. 

 10 figs. , 2 tables. 



INT.-DUP. SEC, WASH., D.C. 



