1.0 Introduction 



Montana Fish, Wildlife and Parks (FWP) monitors trout populations annually on the Madison 

 River. When these surveys revealed that one-year old rainbow trout were disappearing from their 

 annual Madison River population estimates in 1991, there was an intensive investigation to 

 discern why young-of-the-year (YOY) survival, and potential recruitment appeared to have 

 plummeted. Population declines were eventually attributed to the myxozoan parasite Myxobolus 

 cerebralis which causes whirling disease. The Madison River is a renowned fishery and the 

 presence of whirling disease raised concern for the trout populations and associated fishery. 



Annual population estimates have been examined by Vincent and Byorth (1999) to determine the 

 impact of whirling disease on the Madison River fishery. While trout population declines were 

 well documented, the impacts of whirling disease on angling were unclear. Creel surveys were 

 undertaken in 1995 and 1996 to document angling pressure, catch rates, and angler satisfaction in 

 the presence of whirling disease. This report summarizes the 1995 and 1996 creel surveys and 

 compares them with historic creel survey data from pre-whirling disease years; 1976, 1977, and 

 1981. 



The specific objectives of this report are to: 



1. Document fishing pressure, catch rates, and angler characteristics on the Madison River 

 in 1995 and 1996. 



2. Examine creel survey results from 1996 by section, focusing on the FWP study sections, 

 Pine Butte and Snoball. 



3. Compare the 1995 and 1996 results with historical creel data. 



4. Assess the effects of whirling disease on the fishery and its implications for future 

 fisheries management. 



Evaluation of 199$ and 1996 Creel Data and \\s Implications related to Whirling Disease 

 In the Madison River, Montana 



Montana Fish, Wildlife and Paries 

 March 12,2002 



