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BULLETIN OF THE BUREAU OF FISHERIES 
EXPERIMENTAL STUDIES OF THE EFFECT OF OIL 
ON OYSTERS 
REVIEW OF THE LITERATURE 
By Paul S. Galtsoff 
So far as the author was able to ascertain, the literature on the subject is rather 
meager, comprising less than a dozen papers. On the basis of a small number of 
experiments with water-gas tar carried out in 1912 at the United States Bureau of 
Fisheries station at Woods Hole, Mitchell (1914) arrived at the conclusion that in 
constantly renewed sea water tar shows no noticeable effect on oysters. Fatal effects 
are produced however, when considerable quantities of water-gas tar are in intimate 
contact with oysters kept in stagnant water. 
Orton (1924) when studying the causes of the unusual mortality among oysters 
in England during 1920 and 1921, made a few experiments with oil and arrived at 
the conclusion that the petroleum residue is not seriously poisonous to oysters, as 
all of them kept in a jar covered with a thick film of oil survived at least 7 weeks. 
Similar results were obtained in the laboratory of the Scottish Biological Association 
(Orton, 1924). Examination of water made by the Government chemist (Orton, 
1. c., p. 42) showed that the sample of water in which the oysters were kept contained 
traces of the original petroleum waste in solution and in addition small quantities 
of substances of an acidic character. The latter, probably naphtenic acids which 
exist in certain petroleums, may have been present originally in the petroleum waste 
used in Orton’s experiments or may have been derived from the waste by some 
chemical or biological action of the sea water. 
Contrary results were obtained by Leenhardt (1925) who showed that the mortality 
of both European and Portuguese oysters ( Ostrea edulis and Gryphea angulata ) kept in 
water covered with petroleum increases in proportion to the amount of the latter. 
Thus, no mortality was observed in the oysters kept for a month in water containing 
from 0.01 to 0.05 percent petroleum. When the quantity of petroleum was increased 
to 0. 1-0.5 percent only 2 or 3 oysters out of a dozen survived. In the water con- 
taining 2 percent petroleum all oysters died within 1 week. Although Leenhardt 
states that water was changed and presumably the oysters did not suffer from lack 
of oxygen it is not clear how often the water was renewed. From the observations 
that the same mortality occurred in the oysters that never were in direct contact 
with petroleum as in those which were periodically covered with it, simulating the 
conditions on tidal flats, Leenhardt concluded that oil contains a substance soluble 
in sea water, and poisonous to oysters. Unfortunately both Orton’s and Leenhardt 
reports are very brief and fail to give all the details of the experiments. 
More comprehensive investigation on the effect of oil on fish was carried out by 
Roberts (1926) who demonstrated that oil extracts (gas oil, Diesel oil, 600 seconds 
and 1,500 seconds oil) prepared by shaking 100 cc of oil with 2,000 cc of boiled and 
filtered river water are toxic to brown trout. He attributed the toxicity to both 
soluble toxic substances and emulsions. Mention should be made also of the work 
of Stephen (quoted from Roberts, 1926) who described the adverse effect caused by 
a film of paraffin 0.03 mm in thickness on pelagic larvae of plaice and flounders; 
and of the experiments of Jee and Roberts (1923) with fresh-water shrimp killed 
by contact with fuel oil, and with caddis larvae and fresh-water shrimp killed by 
