STUDIES ON FISH MIGRATION II. THE INFLU- 

 ENCE OF SALINITY ON THE DISPERSAL 

 OF FISHES^ 



DK. F. E. CHIDESTER, 

 West Virginia University, :Morganto\vn. W. Va. 



In connection with an extensive study of the factors 

 influencing fish migration, certain experiments were per- 

 formed during the summers of 1919 and 1920 to deter- 

 mine the effects of different salinities on the reactions of 

 fish under laboratory conditions. Besides testing the 

 animals with the salts of sea water, preliminary experi- 

 ments were made with changed temperature and stream 



Material and Methods 

 The apparatus consisted of a two-tributary unit of a 

 river system so arranged that different solutions could 

 be introduced, affording the fish an opportunity to select 

 the more favorable one. Two almost parallel troughs 

 were so directed as to let the solutions flow down into 

 a long receiving trough that had adjustable outlets in 

 the middle. 



There was also an intake at the extreme end of the 

 large receiving trough so that if desired three intakes 

 could be used. When only the two converging troughs 

 were supplied with currents, a partition was placed 

 across the middle of the receiving trough so that the 

 water could flow laterally and eventually escape from 

 the pool by the regular outlet. 



The two tributary troughs were each 10 feet long, 4 

 inches deep and 4J inches wide and the receiving trough 

 was 10 feet long, 8 inches deep and 8f inches wide. The 

 twin troughs were marked off in feet and conspicuously 



Fisheries at Woods Hole, Mass. 



373 



