Laboratory results for trout routinely sampled at Lees Ferry by Arizona Game and Fish Department biologists this spring came back positive for whirling disease on Wednesday, June 13, marking the first time this disease has been documented in wild fish in Arizona public waters.

Whirling disease is a parasitic infection of trout. It gets its name because the parasite infiltrates the head and spinal cartilage of small fingerling trout and can cause the fish to swim erratically (whirl). More information on the disease can be obtained from the Whirling Disease Foundation at www. whirling-disease.org or at http://www.whirlingdisease.montana.edu/.