A STUDY OF THE EFFECTS OF CERTAIN OILS, TARS, 

 AND CREOSOTES UPON BROOK TROUT 

 (Salvelinus fontinalis.)* 



By Adrian Thomas, 



Acting Fish Pathologist, 



Department of Game and Inland Fisheries, Virginia. 



(From the Biological Laboratories of Clark University, f) 



The era of the motor car has brought with it the demand for 

 good roads. Woodblock, stone and asphalt streets are possible 

 in our cities, but the cost of such materials is prohibitive of their 

 use on suburban roads. Gravel alone does not wear well under 

 the heavy traffic and it is necessary to find some material to aid 

 in the building of good roads. Frequently tars and like sub- 

 stances have been employed in the treatment of gravel and 

 macadam roads which improve their wearing qualities, and in 

 many instances have proved to be satisfactory from the point of 

 view of the highway-engineer and the motorist. Many here- 

 tofore waste products are being used as matrices in road con- 

 struction and thus they attain commercial value. 



Though many of these products seem to make good roads, 

 complaints are often made by fishermen, and sportsmen too, that 

 the tar from roads washes into streams and ponds during rains, 

 thus killing the fish or driving them away. Several articles appear 

 in the "Fishing Gazette" during the years 1912, '13 and '14, 

 noting the scarcity of fish in certain streams and ponds, and 

 attributing their absence to the toxic effect of road washings. 

 While the fish themselves may not actually be killed by some of 

 the tars, the larval forms upon which they feed are destroyed, 

 thus forcing the fish to seek localities where they may find food. 



Through the Office of Public Roads a number of samples of 

 materials, used as "road binders" were obtained. Small amounts 

 of these substances have been added to water in which trout 

 were placed and the effects noted. 



* The U. S. Bureau of Fisheries provided the funds for pursuing these 

 experiments and this is published by permission of the Commissioner. 



t The author wishes to thank Prof. R. S. Lillie, of Clark University, for 

 placing at his disposal equipment for this investigation. 



