Upper Midwest Environmental Sciences Center
Efficacy of hydrogen peroxide to control mortalities associated with bacterial gill disease infections on hatchery-reared salmonids
Rach, J. J., Gaikowski, M. P., and Ramsay, R. T., 2000, Efficacy of hydrogen peroxide to control mortalities associated with bacterial gill disease infections on hatchery-reared salmonids: Journal of Aqutic Animal Health, v. 12, p. 119-127.
The efficacy of hydrogen peroxide to control mortalities associated with Bacterial Gill Disease (BGD) was evaluated in three clinical field trials conducted at two Wisconsin Department of Natural Resources hatcheries. Microscopic examination of the fish gills before treatment revealed gill damage and the presence of bacteria indicative of BGD. In separate trials, brown trout (Salmo trutta), chinook salmon (Oncorhynchus tschawytscha), and rainbow trout (Oncorhynchus mykiss) were transferred from the source culture unit into a test system of 12 individually plumbed tanks. Each tank was supplied with a continuous flow of hatchery water at a flow rate providing an exchange rate similar to that of the culture unit. Fish were exposed to hydrogen peroxide concentrations of 50, 100, or 200 µL/L for 30 or 60 min every-other-day for a total of three treatments. In all three trials, at least one of the hydrogen peroxide treatment regimens reduced cumulative fish mortality in comparison with the controls. Exposures of 200 µL/L for 60 min increased the risk of mortality to brown trout and chinook salmon relative to other treatment concentrations. Exposures up to 200 µL/L hydrogen peroxide for 30 min decreased the risk of mortality to rainbow trout. Post-treatment qualitative gill examinations indicated that gills of the treated fish appeared normal (no signs of gill damage) while the gills of control fish exhibited pale coloration, clubbing of filaments, and lamellar fusion. Based on the efficacy data, two static bath treatment regimens were effective in the control of BGD; hydrogen peroxide administered at concentrations of 50 to 100 µL/L as a 60 min exposure or hydrogen peroxide administered at concentrations of 50 to 200 µL/L as a 30 min exposure. Prior to administering any proposed treatment regimen, a preliminary bioassay should be conducted on a small sample of fish to verify the safety of the treatment.
hydrogen peroxide, Bacterial Gill Disease, brown trout, Salmo trutta, chinook salmon, Oncorhynchus tschawytscha, rainbow trout, Oncorhynchus mykiss, hatchery