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