The Montana state fish and wildlife agency says whirling disease has been found among brown trout in Silver Creek, a tributary of Hauser Lake near Helena, Montanta.
Silver Creek is an important spawing area for brown trout.
In the spring of 1996, a test found no signs of the disease among Silver Creek fish, and there is still no evidence that rainbow trout in the Hauser Lake system have been infected. The disease exists in other Montana waters, and is a major concern for state fishery managers. Whirling disease causes a tail- chasing motion in fish, and is fatal.