Water temperatures during the summer 

 vary from 60° F. to the low seventies. Winter 

 water temperatures were collected in 1955 and 

 showed 32° F. on several days. Anchor ice 

 commonly formed on riffles . 



The fish population consists of large 

 numbers of brown and rainbow trout, whitefish, 

 northern mottled sculpins, and longnose dace . 

 The longnose sucker ( Catostomus catostomus ) 

 is present, but rare'. Cutthroat trout have been 

 reported but were not observed by our creel 

 census clerks or by electric shocking. 



Gibbon River 



Gibbon River originates in Grebe Lake 

 and flows about 24 miles to Madison Junction 

 where it joins the Firehole (figure 1) . The 

 stream drops about 1,100 feet for an average 

 gradient of 44 feet per mile . Three falls, which 

 serve as barriers to upstream fish movement, 

 account for a total drop of 169 feet: Little 

 Gibbon Falls drops 25 feet, Virginia Cascades 

 drops 60 feet, and Gibbon Falls drops 84 feet. 



Temperatures in the Gibbon River have 

 never been recorded above 64° F., and it is 

 doubtful if they ever reach 70° F . A few hot 

 springs enter the Gibbon near its mouth and 

 many at Norris Geyser Basin, but the water is 

 probably softer than the Firehole since the 

 conductivity of the Madison was lower (312 

 mhos.) than the Firehole (385 mhos.) and the 

 dilution by the Gibbon must have caused this 

 condition . 



Above Virginia Cascades, the stream is 

 populated with small (3-6 inch) brook trout and 

 grayling. Woodbury (1930) reported rainbow 

 trout but none have been observed recently. The 

 section of stream between Virginia Cascades 

 and Gibbon Falls contains brook trout, grayling, 

 sculpins, and longnose dace . Rainbow trout 

 have been stocked but have not been observed 

 commonly. Below Gibbon Falls rainbow and 

 brown trout are present, in addition to sculpins 

 and longnose dace . 



METHODS 



Creel census 



The creel census used on the Madison 

 River system from 1953 to 1957 was designed 

 to estimate the total fishing pressure and catch. 

 Three men were used on the census of the three 

 rivers from 1953 to 1956; in 1957 two men were 

 used on the Madison and Firehole and no data 

 were collected on the Gibbon . All data were 

 grouped for analysis into two-week periods and 

 into stream census areas (e.g., M-1, M-2, on 

 figure 1). The creel census consisted of fisher- 

 man interviews and fisherman counts. Inter- 

 views were conducted on five 8 -hour days the 

 entire length of each stream during each period. 

 All fishing hours were sampled. Information 

 was collected on location of fishing, date, com- 

 pleted or incompleted trip, and number of fish 

 caught by species. Scale samples were taken 

 from all fish collected from 1954 to 1957. 



Fisherman counts were made five days 

 during each period on each stream . All streams 

 are close to roads and accurate counts were 

 possible. Working hours were scheduled to sam- 

 ple all hours of fishing, and complete counts 

 were made six or eight times each working day. 

 We assumed that each angler observed accounted 

 for one hour of fishing. The total fishing pres- 

 sure by hours for each period was computed by 

 multiplying the average number of fishermen 

 observed for each hour by the number of fishing 

 hours during the period. The total catch was 

 computed by multiplying the catch per hour by 

 the number of fishing hours . The number of 

 fishing trips was computed by dividing the 

 average length of each completed trip by the 

 estimated number of fishing hours each period. 



Experimental stocking 



The same stocking program as followed 

 in recent years was followed in this study since 

 it was necessary to determine its value to 

 anglers . Originally, this study involved the 

 marking of a percentage of the planted fish (both 

 fingerlings and adults) prior to planting, and the 

 checking of creels to determine the number of 

 these fish that entered the catch. The marking 



