in 253 streams and 142 lakes. Rainbow and 'or 

 eastern brook predominated where they were 

 found with cutthroat trout. 



Cutthroat are presently restricted to the 

 headwaters of streams which originally were 

 inhabited by them throughout. Natural bar- 

 riers have aided in restricting non-native spe- 

 cies from invading cutthroat waters above the 

 barriers. Factors influencing their distribution 

 are stream habitat changes, competition with 

 non-native species and crossing with rainbow 

 trout. No single characteristic was found to 

 be adequate for identification of cutthroat, 

 but when a combination of characteristics were 

 used satisfactory separation of fish over four 

 inches long was achieved. Much of the prob- 

 lem in identification was caused by crossing 

 of cutthroat and rainbow. Their progeny have 

 characteristics of both species. 



Southeast Fisheries District 



During the biennium surveys were con- 

 ducted on 63 streams, 13 natural lakes, and 

 four irrigation reservoirs. Two lakes were 

 sounded, mapped and volumes calculated in 

 preparation for future rehabilitation. 



Many applications for fish to stock farm 

 and ranch ponds were reviewed and recom- 

 mendations made. Detailed surveys were made 

 on three ponds; less intensive surveys on many 

 others. Most farm and ranch ponds in Mon- 

 tana were built for stock watering, irrigation, 

 flood control and erosion control rather than 

 for fishing; consequently, most are not suitable 

 for sport fish production. An effort is made, 

 however, to develop those ponds that have 

 sport fishing possibilities, particularly in east- 

 ern Montana where fishing waters are often 

 scarce. 



A preliminary investigation was made on 

 loss of fish habitat due to a recent Agricul- 

 tural Conservation Program on Rock Creek 

 (Carbon County) for flood control and repair 

 A more detailed im e: ligal ion on the ifl.it ion 

 hip between I'lo i ing inten: ity and 



quality of the stream for fish production is in 

 progre 1 1 on Rock < Ireek 



Five creeks were Investigated as possible 

 sites I'm i tudj of the eJ Eectj oi edimenl on 

 wild trout. 



Dm ing 1958 a compacl earth dike, enclos 

 ing a 20-acri rectangle, was built to create 



Branum Lake, a fishing lake at Miles City. 

 This is in an area that has had limited rec- 

 reational fishing because of unsuitable reser- 

 voirs and the absence of natural fish habitat. 

 The Custer Rod and Gun Club paid initial 

 pumping costs to fill the reservoir with water 

 from Tongue River. Water lost by evaporation 

 is replaced by a pump and well incorporated 

 in the project and with waste water pumped 

 from the adjacent Federal Fish Hatchery. 



Cooney Reservoir and portions of streams 

 tributary to this reservoir were chemically- 

 treated in October 1958 to eliminate carp in 

 the reservoir and to reduce numbers of other 

 undesirable fish in the drainage. Toxaphene 

 was applied to the reservoir and the streams 

 were treated with a combination of toxaphene 

 and liquid rotenone-based toxicants. This is 

 an irrigation storage reservoir where, in spite 

 of heavy trout planting, fishing had become 

 poor due to the increase of carp and suckers. 

 The reservoir has been restocked with rain- 

 bow trout which are expected to grow to 

 catchable size during the summer of 1960. 



Lost Lake was chemically treated during 

 September 1959. It is an alpine lake located 

 in the Custer National Forest on the Lake 

 Fork of Rock Creek in the Beartooth Plateau. 

 The lake contained many suckers which were 

 probably introduced by fishermen using small 

 suckers as bait. It is a considerable distance 

 from the normal range of suckers; then 

 this unwanted guest not only limited pro- 

 duction of desirable fish in the lake but was 

 a potential source of contamination of other 

 nearby waters. 



Willow Creek Reservoir and part of Lodge 

 grass Creek were chemically treated in Maj 

 1950 to control carp, suckers, pumpkinseeds, 



chubs, and shiners. These fish made up more 



than 90 per cenl of the fish in this body of 

 water. Approximate^ 225 -.aliens of toxicant 

 were aerially applied to the reservoir, and the 

 inflow im: waters weir tieated by dripping 

 chemicals into the water above the diversion 

 structures on Lodgegrass Creek, The water 

 is expected to be non toxic and suitable for 

 planting fish bj the summer of I960 



Northeast Fiahe 



District 



Highlighting the fisheries activities of tin- 

 area during the biennium was the construe 



28 



