lower Boulder River and the East and West 

 Boulder Rivers; fishermen creels, however, 

 averaged 65 per cent rainbow trout. 



A general survey of the Big Hole River 

 Drainage was made during the 1959 field 

 season. Fish in the tributaries of the Big Hole 

 River were sampled with the electric shocker 

 and scale samples were taken for age and 

 growth studies. Most of the mountain lakes 

 in the Big Hole Drainage that were accessible 

 by road were surveyed and, in addition, sur- 

 veys were made on ten lakes in the drainage 

 that could be reached only by pack outfit. 



During the past year work on a large 

 electric shocker that will permit sampling 

 fish in some of the larger streams has pro- 

 gressed nicely. Better management of the 

 sport fishery in the larger streams can be 

 realized if the actual numbers and species 

 of fish there can be determined. 



Following the August 1959 earthquake in 

 the Madison River area, fish were sampled in 

 the river below the slide. Good numbers of 

 trout and whitefish were present. The im- 

 portance of wild trout was clearly demon- 

 strated at this time. In spite of relatively 

 heavy planting only one trout in ten was a 

 hatchery fish. Temperatures and turbidity in 

 the Madison River as they may be influenced 

 by changes resulting from the quake will be 

 closely followed. 



Fish and game personnel check the upper Madison 

 River to determine effects of the 1959 earthquake. 



(Photo by George Holton.) 



Central Fisheries District 



Nineteen lakes and impoundments were 

 surveyed during the biennium. Information on 

 size, volume and fish numbers was gathered 



Light, portable equipment is used on mountain lake 

 surveys. (Photo by Tom Smith.) 



for use in future management. Fish in five 

 streams were studied by means of an electric 

 shocker. Sampling stations were set up on 

 Belt Creek, and water quality standards are 

 being established for use in determining the 

 effects of any future mine-mill pollution. 



A method for measuring the ability of 

 water to produce fish is needed. This problem 

 is being approached from three angles: fish 

 growth, total dissolved solids, and periphyton 

 production. Several streams are being sampled 

 regularly. Some phases of this study are being 

 carried out by the department's fishery labora- 

 tory, and the balance is being conducted in 

 the Central Montana Fisheries District. 



Rehabilitation to remove rough fish and 

 reintroduce trout was carried out on six lakes 

 and reservoirs and one stream. Follow-up 

 surveys were carried out on the Marias River, 

 Kipp Lake, Eureka Reservoir and Tunnel Lake 

 in order to determine the results of previous 

 rehabilitation and replanting. All had good 

 numbers of trout. Nine private ponds were 

 rehabilitated during this period with owners 

 paying the cost of rehabilitation and replant- 

 ing. 



Cutthroat trout (Salmo clarki ) originally 

 inhabited all Montana waters in and adjacent 

 to the mountains, except for a considerable 

 number of small isolated virgin lakes. To aid 

 in the management of this fine native trout, a 

 study on the distribution of cutthroat and the 

 factors affecting them was completed. Cut- 

 throat were recorded from 699 streams and 

 244 Montana lakes. They were predominant 



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