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Wisconsin. State Conservation Committee (1915-27) / Biennial report of the State Conservation Commission of Wisconsin for the years 1915 and 1916
(1916)

Lowe, John N.
The effect of gasoline and benzine on the parasitic copepod, salmincola edwardsii olsson, parasitic on the gills of the brook trout,   pp. 31-33 PDF (695.2 KB)


Page 31


                        BIENNIAL REPORT                          31
THE EFFECT OF GASOLINE AND BENZINE ON THE
   PARASITIC COPEPOD, SALMINCOLA EDWARD-
     SIH OLSSON, PARASITIC ON THE GILLS OF
                    THE BROOK TROUT.
                        By JOHN N. LOWE.
  On or about July 8, 1916, Mr. James Nevin, Chairman of the Conserva-
tion Commission, requested me to perform experiments with gasoline with
a view of determining whether it would destroy the parasitic copepod
(Salmincola edwardsii Olsson) which is parasitic on the gills of the brook
trout (Salvelinus fontinalis).
  Three hatcheries were visited during the investigation, viz. Madison,
Wild Rose and Bayfield.
  The hatchery at Wild Rose presented the most extensive infection,
the adult trout being most affected, but the young fish (fry) were found
to
be infested with one or more parasites. At Madison the adult fish were
not as extensively infected as at Wild Rose but the condition was serious.
The young fish (fry and year old) were found to be entirely free from the
parasite. The young fish are kept in ponds which are entirely free from
all sources of contamination. The Bayfield hatchery presented a different
problem and has conditions which are more difficult to overcome. The
water coming from Pike's creek is a constant source of infection as it was
found that the "wild" trout were infected by the parasite. Nevertheless,
it was found upon examination of the fish that the percentage of fish
attacked by the parasite was less than at Wild Rose.
  The experiments were performed at the Madison and Wild Rose hatch-
eries. The fish were exposed to gasoline and benzine for varying periods
of time. A stop watch was used for recording time. The copepods were
examined with a pocket lens magnifying 14 diameters, or with the lower
power (h) of a compound microscope.
  The fish placed in gasoline or benzine did not show any discomfort for
the first fifteen or thirty seconds. After this period they jumped a great
deal and gasped. In about two or three minutes they were suffocated or
nearly so. The mucus secreted by the glands covered the entire body. It
was creamy white due to the coagulation.
  The recovery of the fish was interesting in these experiments. The gao-
line penetrated into the tissues of the fish. The gills were covered with
an
oily film, which inhibited the respiratory functions of the fish and its
recovery for a short time. When the fish were returned from gasoline to
water, they remained on their sides from five to twenty-five minutes,
depending upon the length of time they were kept in the gasoline and
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