Survey information was collected from ten 

 streams during the past two years. An intensive 

 study on the Marias River below Tiber Dam was 

 completed which provided considerable information 

 valuable to fishery management. This study included 

 an evaluation of the effects of the Tiber impound- 

 ment on the river downstream from Tiber Dam. Fish 

 habitat in the Marias River immediately below Tiber 

 Dam was greatly improved by the reservoir acting 

 as a settling basin for the otherwise silty Marias 

 River. This improved habitat has been providing 

 good trout and sauger fishing. Efforts to stabilize the 

 flow in this area of improved habitat, if successful, 

 could extend this area and further improve the 

 fishery outlook in the Tiber-Marias area. 



Rehabilitation to remove rough fish and re-estab- 

 lish trout was accomplished on nine lakes and 

 reservoirs and three streams. Three private ponds 

 were rehabilitated with owners paying the cost of 

 rehabilitation and planting. 



During the summer of 1961 many of the waters 

 in the district dropped to extremely low levels— some 

 streams and lakes dried up completely. Because of 

 this, many adjustments had to be made in planting 

 schedules. Bynum, Marlinsdale and Harris Reser- 

 voirs were drawn to the lowest levels in many years. 

 Low levels offered the opportunity to rehabilitate 

 economically, so rough fish were removed by chemi- 

 cal treatment. These reservoirs have since been 

 planted with rainbow trout. 



Cutthroat trout were introduced into two streams 

 in the upper Sun River drainage and one stream in 

 the Judith River drainage. Evaluation of the success 

 of these plants is being continued. 



Considerable trout stream habitat was lost due 

 to stream channel alteration in the district over the 

 past two years. Channel changes were made on 

 several important trout streams to make way for 

 road construction, additional crop land and other 

 purposes. Some of this stream alteration could have 

 been prevented if it had been subjected to review in 

 the planning stages. 



SOUTHEAST FISHERIES DISTRICT 



Investigations in Montana have consistently 

 shown that wild trout in streams provide the majority 

 of the fish for the creel. Therefore, this district has 

 concentrated on projects to maintain future stream 

 fishing. 



During the biennium a stream sediment investi- 

 gation project was undertaken. The Montana Fish 



and Game Department and many Montana sports- 

 men are concerned about the harmful effects of 

 sediment from agricultural pollution on trout streams. 

 We know that heavily silted streams are not good 

 fishing streams. We also know that the vast majority 

 of trout caught from our streams are wild trout — fish 

 that grew from eggs incubated in the clean stream 

 gravel. 



The future of stream fishing in Montana will 

 depend largely on how many of these wild trout our 

 streams will produce. Therefore, it is to the benefit 

 of Montana, both from an economic and recreational 

 standpoint, to keep streams in a suitable condition to 

 produce trout. In order to maintain and improve the 

 capacity of our streams to produce trout, we must 

 know the specific requirements of trout and we must 

 also know the specific conditions harmful to them. 



We are now studying the effects of agricultural 

 pollution on trout. Our study considers silt in streams 

 accompanied by low streams flows and high water 

 temperatures, and the effects of these agricultural 

 pollutants on trout. 



Bluewater Creek is one of our study streams — an 

 example of a stream affected by agricultural pollu- 

 tion. The use of the water from this stream is fairly 

 typical of situations found in other trout streams in 

 Montana. Diversion ditches take cool, clean water 

 out of the stream. Some of this water is used to 

 irrigate cultivated cropland. Unused water is re- 

 turned to the creek via waste water ditches, warmer 

 and dirtier. 



How does agricultural pollution affect trout in 



Specialized equipment is used to measure oxygen content of ■ 

 moving through stream-bed gravel. 



