13 Rainbow 



■ Brown 



D Mountain whitefish 



Figure 14. Proportion of catch from anecdotal data provided by a Madison River angler based on his 

 fishing log from 1986 to 1995. No information was provided for cutthroat trout. 



5.1.2 Angling Pressure 



Angling pressure is used as an index of how much "pressure" is applied to a fishery. However, 

 because methods used in 1995 and 1996 creel surveys were so different in terms of the level of 

 effort and the types of surveys used comparing these pressure estimates may not be the a robust 

 way to examine angler use. A more continuous and consistent set of data exists in the biennial 

 mail-in angler surveys collected by FWP. Figure 15 depicts data fi-om responses to mail-in 

 surveys from 1968 to 1999 for the section from Ennis Lake to Hebgen Reservoir which 

 encompasses much of the area surveyed in 1995, 1996, and the creel surveys from earlier years. 



Angling pressure generally appears to have increased from the 1960's to the present, but has 

 fluctuated since an initial 28% increase from 1984 to 1985. It is difficult to know what caused 

 the fluctuations in angler use from 1985 to 1997, but the declines in 1995 and 1997 may be 

 attributable to anglers avoiding the Madison River due to reports of the impact of whirling 

 disease on the fishery. Since the discovery of whirling disease in the Madison was first reported 

 in the mass media in December of 1994, it would be reasonable to assume that some of the 25% 

 decline in angler use from 1993 to 1995 might be due to anglers avoiding the area either because 



Evaluation of 1995 and 1996 Creel Data and Us Implications related to Whirling Disease 

 In the Madison River, Montana 



Montana Fish, Wildlife and Paries 

 March 12, 2002 



26 



