AN EXPERIMENTAL STUDY OF THE MOVEMENTS 

 OF HERRING AND OTHER MARINE FISHES.^ 



VICTOR E. SHELFORD AND EDWIN B. POWERS. 



I. Introduction 315 



II. Material and Methods 317 



1. The stock of fishes 317 



2. The water supply of the station 317 



III. The resistance of fishes to contamination and decomposition products. . 320 



IV. The reactions of fishes to chemical conditions in sea- water 323 



1. Conditions and methods of study 323 



2. Temperature 325 



3. Hydrogen Sulfide ; 326 



4. Salinity and alkalinity and acidity 326 



5. Oxygen 331 



V. Summary and Discussion of Conclusions 332 



VI. Acknowledgements and Bibliography 333 



I, Introduction. 



The general problem of increasing the supply of any species 

 of fish or any other aquatic food animal, or of maintaining such 

 species against extensive catch and against pollution of waters 

 with sewage and the waste products of manufacturies, is very 

 complex. The older methods of study are as important now 

 as ever. The study of the food of an animal, its relation to its 

 natural enemies, and its breeding habits still must receive their 

 proper share of attention. In addition to these we now know 

 that attention must be given to the chemical condition of the 

 water, its effect on the movements and migrations and general 

 health of the animals. Likewise it is especially important to 

 study the physical and chemical conditions in which the animals 

 breed and to look especially into the matter of the preservation 

 of the natural breeding grounds. It is well known that one of the 

 reasons for the depletion of the white-fishes in Lake Michigan 

 is the destruction of their breeding grounds by the addition of 

 sewage, saw-dust and other refuse to the water, which has 

 settled on the breeding grounds and rendered them uninhabitable 



1 Contribution from the Puget Sound Marine Station. 



315 



