FISHERIES 



Montana is truly a great fishing state. Her trout streams are unexcelled. A few years ago 450 

 top American sport fishing experts completed a 4-year survey and selected the 100 best trout 

 streams in the country. Twelve of the 100 were in Montana, and the Madison River was named as 

 the nation's number one trout stream. Each year trout from Montana waters receive honors in a 

 fishing contest conducted by a national sports magazine. 



Although best known for trout, Montana has good bass, walleye, sauger, kokanee, northern 

 pike, paddle fish and whitefish fishing as well. Grayling are more numerous here than in any other 

 state except Alaska. 



Fish Habitat Preservation 



In working to perpetuate this valuable re- 

 source, Montana fisheries biologists are among 

 leaders in the nation on studies and action 

 programs to protect trout habitat in streams. 

 Habitat is the natural abode or home of an ani- 

 mal. An animal, species or community of ani- 

 mals can be destroyed as surely by subtle 

 changes in habitat as by annihilation with poi- 

 son. Habitat is the key to wildlife abundance. 



During the biennium a study on the effect 

 of silt on trout streams was completed. It 

 showed that large sediment concentrations in 

 a stream are disasterous to trout production. In 

 Bluewater Creek, Carbon County, large sedi- 

 ment concentrations practically eliminated in- 

 sects important as trout food, eliminated trout 

 reproduction, and in turn the trout population. 

 Grayling eggs and kokanee eggs fared no bet- 

 ter than rainbow, cutthroat and brown trout 

 eggs; however, sucker eggs were able to with- 

 stand sediment with little loss. 



Since 1957 the Department has assigned a 

 fisheries biologist to the position of Pollution 



Control Biologist. During the biennium he has 

 investigated water quality and pollution prob- 

 lems on various streams of the State. This in- 

 cluded a study of the effects of aerial applica- 

 tion of DDT near Boulder, Montana by the U. 

 S. Forest Service. Dead fish, mostly trout, were 

 recovered from waters in this area and dead 

 frogs were reported in a pond. Large numbers 

 of aquatic insects (fish food) were killed in the 

 streams and complete insects kills occurred in 

 some stream sections. Sampling one year af- 

 ter the spraying indicated that the aquatic in- 

 sect population has substantially recovered 

 with the exception of caddis flies at some sta- 

 tions. 



A department-supported doctoral thesis, 

 THE EFFECT OF DDT ON COLD WATER FISH 

 AND FISH FOOD ORGANISMS, was completed 

 during the biennium. Among other findings, 

 delayed mortality occurred during a six-month 

 observation period in all species of fish treated 

 with DDT. Aquatic insects in a test stream 

 were reduced 99 percent following application 

 of DDT at one pound per acre (the rate then 



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