Originating at the confluence of the Big Hole and Beaverhead 

 rivers, the Jefferson flows 77 miles in a northeasterly 

 direction, with its only major tributary, the Boulder River, 

 entering from the north near Cardwell. 



Fisheries 



The Madison River was one of two rivers in Montana that 

 received a Class I designation in the sport fishery value for its 

 entire length. Six reaches of the Madison were rated and each 

 accumulated points separately to receive a Class I sport fishery 

 value. Being a Class I sport fishery is nothing new to the 

 Madison; from the first state river classification in 1959, the 

 entire Madison has been "blue ribbon". A total of 281,586 angler 

 days were estimated in 1985 on the Madison, which accounted for 15 

 percent of the total estimated fishing pressure statewide. Of the 

 102 tributaries of the Madison below the park boundary, 89 reaches 

 in 405 miles were identified in the fishery data base (Tables 35 

 and 36.) Due to lack of sufficient fisheries information, only 47 

 (53 percent) of the reaches in 350 miles could be assessed. 



As with the Madison, high sport fishery values dominated the 

 fishery assessment in the Gallatin River drainage as well. 

 Eighty-five miles of the Gallatin and its two forks received a 

 Class I or II sport fishery value. The 30-mile stretch of the 

 West Gallatin from the west fork to Gallatin Gateway received a 

 Class I in this category. Only the lower seven miles of the West 

 Gallatin and 22 miles of the East Gallatin were rated a Class III 

 in the sport fishery value. The lower reaches of the West 

 Gallatin suffer from severe dewatering. Of the 117 reaches in the 

 Gallatin drainage in the fishery data base, only 49 reaches could 

 be assessed. However, the unassessed reaches accounted for only 

 85 of the 396 miles in the drainage. 



Portions of the Jefferson River's fishery have been depressed 

 by severe dewatering during the summer irrigation season. Despite 

 this dewatering, the Jefferson has been able to maintain a Class 

 II sport fishery value throughout its length. Abundant 

 populations of brown trout and whitefish, with lesser numbers of 

 rainbow trout, maintain the high-valued fishery. The Boulder, 

 impacted by historic mining pollution, severe dewatering and 

 habitat loss due to channel alteration, did not fare so well in 

 the Montana Rivers Study. All but 14 of its 67 miles received a 

 Class IV in the sport fisheries value. 



Of the 20 reaches in the Missouri headwaters receiving a Class 

 I or II in the habitat and species value, only four contained 

 species of special concern. Where arctic grayling and westslope 

 cutthroat trout reigned 100 years ago, grayling have been 

 documented in only three streams today. Although only one 

 genetically pure population was identified in the data base, 

 recent analysis of westslope cutthroat from streams in the 



90 



