Sauger 47 



Fish Size 47 



Population Estimates 51 



Habitat Preference 52 



Tagging Studies 52 



Channel Catfish 52 



Fish Size 55 



Catch Rates 57 



Tagging Studies 58 



Instream Flow Requirements of Indicator Species 58 



Passage and Spawning Flows 60 



Rearing Flows 60 



Monthly Instream Flow Requirements 62 



IMPACTS OF WATER WITHDRAWALS 65 



The Naturally Occurring Pattern of Low Flows 65 



Impacts of Increased Future Use 65 



Projections of Future Use 65 



Impacts of Reduced Streamflow 67 



Impacts on Water Quality 71 



Other Limiting Factors 72 



Limiting Factors Unrelated to Flow 73 



SUMMARY 75 



PART II. TONGUE RIVER RESERVOIR FISHERY STUDY 77 



INTRODUCTION 79 



Purpose 79 



Study Area 79 



METHODS 83 



Sampling for Water Chemistry Analysis 83 



Fish Sampling 83 



Population Estimates 83 



Creel Census 84 



EXISTING SITUATION 85 



Limnology 85 



Fish Populations 85 



History 85 



Sampling Results 87 



Creel Census 107 



IMPACTS OF WATER WITHDRAWALS Ill 



Projection of Future Use Ill 



Impacts on the Reservoir Fishery Ill 



SUMMARY 113 



