Dead Fish not Likely from Milfoil Control

The Idaho Department of Fish and Game has received several calls during the past week regarding dead fish in many Coeur d'Alene area lakes. Dead fish were reported on the bottom and floating on the lake surface. Reports from concerned anglers and members of the public indicate the dead fish appeared around the time of the application of herbicide to control a milfoil infestation in Hayden Lake, just north of Coeur d'Alene in Kootenai County. Callers also reported dead fish in lakes that did not receive herbicide treatment. Fish and Game officials have investigated the situation and determined that the fish most likely died from stresses related to spawning and not as a result of the application of milfoil controls. The dead fish include adult bullheads, crappie and smallmouth bass. Young of year fish were noted alive in the lake. Only adult fish were found dead. The investigation has shown that some fish had died before and some after the herbicide application. The annual application of herbicide to control milfoil infestations is done by the Kootenai County Noxious Weed Control Department. The applicators followed all established protocols. But with the dead fish appearing close in time to the application, many callers were concerned the herbicide caused the fish to die. Fish and Game also investigated reports of dead fish from Avondale Lake, a small private lake near Hayden. Avondale Lake was not treated for milfoil. The losses on Avondale Lake were primarily bluegill and also appear to be the result of spawning activity. While it is not unusual to see dead adult fish in area lakes in the spring because of stress and weakened condition from spawning, dead fish are usually observed several weeks earlier than this spring. The lakes remained cold much longer this spring than normal, and the colder water caused a delay in fish spawning. Dramatic, recent water temperature changes may also have placed additional stress on spawning fish. Post spawn mortality is common in warm water fish, and is not likely to affect overall populations. For more information on the Eurasian Milfoil Treatment program go to www.kcweeds.com or call 208-446-1290. For more information on this news release, contact Idaho Fish and Game at 208-769-1414.