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The Fish and Game Department has long 

 realized the necessity for a clearer understanding 

 of the problems confronting us in the relation of 

 irrigation to fishing. In the spring of '41 a re- 

 search program was started with the main thought 

 in mind of bringing out the effectiveness of exist- 

 ing fish screens and the comparative losses of 

 trout and other fish in these ditches. In view of 

 the limited funds, the survey was confined to the 

 waters of the Yellowstone drainage and, although 

 this area requires further investigation, the find- 

 ings up to date bring out many pertinent facts 

 and many of the findings can be applied to other 

 irrigation and diversion problems elsewhere in 

 the State. 



A total of over 450 irrigation diversions were 

 found to exist on the waters of the Yellowstone 

 drainage alone. In view of such a large number 

 existing on one drainage, it can be safely stated 

 that there are at least 2,000 diversions located on 

 waters throughout the State. It was found that 

 we have installed in the last several years a total 

 of 29 fish screens and of this total only 3 were 



Oregon type fish screen with 

 rotating- grills — self-cleaning. 



still in shape to operate satisfactorily. Most of 

 these installations averaged close to $800 each 

 and some even more when the items of concrete 

 work, installation, and other incidental expense 

 were taken into consideration. It was also found 

 that the average upkeep and maintenance cost 

 would be approximately $150 annually. Multiply 

 this figure by 2,000 (the number of ditches in 

 Montana) the annual maintenance load would 

 total $300,000, which is three times as much as 

 is available for the operations of the Fisheries 

 Division. 



What we are faced with is a more practical 

 and economical solution to this huge problem. It 

 cannot be denied that many drainages are in need 

 of such a program, but there are also others where 

 the diversions are so large and numerous that 

 the remaining watershed is left entirely dry, or 

 it any water does remain to flow down the stream 

 the temperatures become too high during the hot 

 summer months for fish life to exist. It would be 

 wise to dedicate such watersheds to agriculture 

 and confine the plantings of trout to waters not 

 so adversely effected and thereby give the sports- 

 men better fishing in those waters dedicated to 

 recreation. 



Many sportsmen's organizations and indi- 

 viduals express the thought that the installation 

 of fish screens throughout the State would end all 

 future propagational worries and an abundance of 

 fishing would be available for everyone. How- 

 ever, there are other factors which must be con- 

 sidered and which in many cases are entirely 

 overlooked. One is the fact that we have large 

 drainages in this State, such as the Flathead and 

 Kootenai where not a single irrigation diversion 

 exists, but a survey will show that fishing has 

 declined just as much in these waters as those 

 having diversions. 



This can lead us to only one conclusion, 

 which is that fishing pressures and creel limits 

 have been in excess of our ability to restock and 

 an enlarged propagational program or reduced 

 creel limits must also play their part to bring 

 about better fishing in all waters. 



