IAFWA Research Update on the Target Animal Safety of Chloramine-T to Cool- and Warmwater Fish.

Mark P. Gaikowski and Wendi J. Larson
Upper Midwest Environmental Sciences Center, U.S. Geological Survey.  
2630 Fanta Reed Road, La Crosse, Wisconsin, 54603.  
phone: 608-781-6284  e-mail: mark_gaikowski@usgs.gov


Although chloramine-T is still undergoing efficacy trials through the Investigational New Animal Drug 
(INAD) permit process, a tentative maximum therapeutic regimen of 20 mg/L for 60 min administered on 
four consecutive days has been proposed as the maximum concentration for a New Animal Drug 
Application (NADA) label.  Chloramine-T safety was evaluated by exposing coolwater (walleye, northern 
pike, and lake sturgeon) and warmwater (channel catfish and largemouth bass) fry and fingerling to four 
exposures on consecutive days of 1, 3, 5, and 10X the 20 mg/L proposed label maximum (0, 20, 60, 100, 
and 200 mg/L).  Endpoints measured were acute toxicity, changes observed during gross necropsy, and 
feeding behavior.  Additional tests were also conducted to evaluate the effect of exposure temperature, 
duration, and lifestage in channel catfish and walleye fry and fingerlings.  Treatments of 100 and 200 mg/L 
were either toxic or caused changes in feeding behavior in most fish.  Temperature and exposure duration 
increased the toxicity of chloramine-T.