DANGER TO FISHERIES FROM OIL AND TAR POLLUTION 
OF WATERS.' 
By J. 8. GuTseE., 
Scientific Assistant, U. S. Bureau of Fisheries. 
Recently the casting of oil on already sorely troubled waters has 
increased at such a rate, has been accused as the source of so many 
ills of fishermen and shell fishermen and even of ornithologists, and 
has become such an obviots nuisance, that a considerable realization 
of the extent of the contamination and a sense of the possible evil 
effects have been aroused. So great is the discharge of aig of various 
sorts that in this country it has been proposed to skim off the oil 
from some harbor waters and make it available by proper treatment. 
In Switzerland a patent has been taken out for the recovery of oils 
from backwaters. It is very desirable, therefore, to present a brief 
review of the information available regarding the extent and nature 
of oil and oil-like pollutions with consideration of the possibilities 
of danger therefrom. 
SOURCES OF POLLUTION. 
Danger of fatal contamination from the poisonous substances seems 
to lie chiefly in the gas plants and petroleum distilleries, which on one 
occasion or another, if not regularly, find it convenient to let certain 
products drain into the nearest body of water; in tankers and oil- 
engined craft, which are able to use tar, tar oils, and a great variety 
of petroleum distillates; in oil-burning steamships; and in the wash- 
ings of oils and tars from roads. 
Gas houses and oil refineries are located on all sorts of bodies of 
water larger than brooks. In smaller streams, and particularly in 
those inhabited by salmonids, discharges are Hibtibtless frequently 
fatal to fish life and quite ruinous to the fish value of the water. In 
larger bodies the actual destruction of fish is apt to be small or incident 
to exceptional discharges, and the chief harm probably will come 
from the uninhabitability of the water, especially if this means the 
rendering unfit of a spawning ground or the forming of a barrier 
thereto as for salmon or shad. 
In streams large enough for steamers, and in all larger bodies of 
water, there are added to the contributions from gas houses and 
refineries those from tankers and other ships, and the dangers to 
fishes from poisoning or coating of gills are correspondingly increased. 
These larger navigable bodies may be spawning grounds and are 
almost sure to be gateways to what should be spawning grounds. 
The danger here, therefore, of keeping fish away from the spawning 
1 Appendix VII to the Report of the U. S. Commissioner of Fisheries for 1921. B. F. Doc. 910. 
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