Green River and Flaming Gorge Reservoir Post Impoundment Investigations 1967 Addendum Progress Report No. 4, Job No. 1 B Fishery Investigations, Flaming Gorge Unit Section 8 Progress, Flaming Gorge Unit Colorado River Storage Project Fishery Survey of Fontenelle Reservoir • and the Green River Downstream to Flaming Gorge Reservoir „Wyoming Game and Fish Commission - James B. White, TABLE OF CONTENTS Page Abstract 1 Introduction 4 Methods 6 Results, Fontenelle Reservoir 9 Chemical and Physical 9 Temperature 9 Dissolved Oxygen 9 Alkalinity 10 Hydrogen Ion 11 Total Hardness 11 Turbidity 12 Electrical Conductivity 12 Bottom Fauna 12 Plankton 1 3 Fishery 15 Composition, Abundance, and Distribution 15 Rainbow Trout 16 Brown Trout 17 Whitefish 18 Flannelmouth Sucker 19 Carp 20 Bonytail Chub 20 Utah Chub 21 Bluehead Sucker 21 Forage Fish 21 Harvest 21 Food Habits 21 Results, Green River Section I 24 Chemical and Physical 24 Turbidity 25 Hardness 25 Bicarbonate 25 Sulfate 25 Chloride 26 Electrical Conductivity 26 Hydrogen Ion 26 Temperature 27 Bottom Fauna 27 Fishery 28 Section II Chemical and Physical 29 Turbidity 31 Hardness 31 Bicarbonate 31 Sulfate 31 TABLE OF CONTENTS cont'd: Section II Chloride 32 Electrical Conductivity 32 Hydrogen Ion 32 Temperature 32 Bottom Fauna 32 Fishery 33 Composition, Abundance and Distribution 34 Length, Weight and Condition 34 Food Habits 37 Age Composition 38 Section III, Fontenelle Reservoir Chemical and Physical 39 Turbidity 41 Hardness 41 Bicarbonate 41 Sulfate 42 Chloride 42 Electrical Conductivity 42 Hydrogen Ion 42 Temperature 43 Bottom Fauna 43 Fishery 44 Composition, Abundance and Distribution 44 Length, Weight and Condition 45 Food Habits 46 Age Composition 46 Section IV Chemical and Physical 49 Bottom Fauna 51 Fishery 52 Exploitation of the Green River Fishery 52 Trout Movement 54 Spawning 55 Discussion 55 LIST OF TABLES Table Page 1. Summary of Trout Stocking in the Green River and Fontenelle Reservoir, 1963 - 1966 ................ 5 2. Food Habits of 50 Rainbow Trout and 20 Brown Trout from Fontenelle Reservoir, 1965 and 1966 ............. 23 3. Bitter Creek Water Composition on March 21, 1966, during the Lowland Runoff (in ppm) ............. 24 4. Alkali Creek Chemical Composition ........... 29 5. Chemical Composition of the Big Sandy River.......... 30 21, 1966, 6. Chemical Composition of Dry Creek on March ........... (in ppm) 30 (K) 7. Mean Length, Weight and Condition Data for Fish...... in Section II 35 8. Food Items of 51 Rainbow Trout Stomachs from Section II, Green River, 1965 - 1966 (all sizes combined). — 36 9. Average Lengths for Each Rainbow Trout Age Class in Section II ... 38 10. Water Chemistry of Slate Creek (in ppm) ... 39 11. Water Chemistry (in ppm) and Physical Data for East Side Flume Creek and the Green River upstream from the Mouth of Flume Creek ... 40 12. Average, Length, Weight and Condition of Fish in Section III during Fiscal Years 1966 and 1967 ... 47 13. Food Items of 32 Rainbow Trout Stomachs from Section III, Green River, 1965 - 1966 ......................... 48 14. Average Lengths for Each Rainbow Trout Age Class in Section III....... 49 15. Mean and Extreme Values (ppm) of Green River Water Chemistry, Section IV, (Names Hill Only), 1965 - 1967 50 16. Green River Creel Census Summary, 1966 ... 60 17. Aerial Fishermen Counts on the Green River from Flaming Gorge Reservoir to Fontenelle Reservoir during June, July, August and September, 1966 ... 61 LIST OF FIGURES Figure Page 1. Map of the Green River Study Area Showing Sections and Locations of Benthic Sample Stations ... 62 2. Monthly Surface Area at Fontenelle Reservoir from July, 1965 to July, 1967 ... 63 3. Mean Weekly Discharge of the Green River at the Fontenelle Dam Gage from July, 1965 to September, 1966 .... 64 4. Map of Fontenelle Reservoir Showing Maximum (B) and Minimum (A) Water Levels .... 65 5. Fontenelle Reservoir Water Chemistry as Related to Depth in August, 1965 .... 66 6. Seasonal Fluctuations in Fontenelle Reservoir Water Chemistry from August, 1965 through May, 1967 .... 67 7. Plankton Abundance in the Surface to Ten Foot Strata of Fontenelle Reservoir from August, 1965 to May, 1967 .............................................. 68 8. Vertical Distribution of Plankton in Fontenelle Reservoir in August, 1965 and 1966 ................ 69 9. Composition of the Fontenelle Reservoir Fish Popula- tion as Indicated by Gill Net Catches in the Fiscal Years 1966 and 1967. (July 1 to June 30) .......... 70 10. Length Frequency of Rainbow Trout in Fontenelle Reservoir as Indicated by Gill Net Catches in Fiscal Years 1966 and 1967 (July 1 to June 30) 71 11. Mean Lenghts attained at Various Ages by Rainbow and Brown Trout in Fontenelle Reservoir. Age as determined from Scales and Otholiths taken from Gill Net Caught Trout .... 72 12. Number and Volume of Organisms in Square Foot Bottom Samples taken at Station 1 from October, 1965 through April, 1967 ....73 13. Composition of Square Foot Bottom Samples taken at Station 1 from October, 1965 through April, 1967... 74 14. Number and Volume of Benthic Organisms in Square Foot Samples Taken at Station II from October, 1965.... through April, 1967 75 List of Figures cont i d: Page 15. Composition of Square Foot Bottom Samples taken at Station II from October, 1965 through April, .... 1967 76 16. Composition of the Fish Population Section II of the Green River as indicated by sampling during the Fiscal Years 1966 and 1967 (July 1 to June 30). 77 17. Number and Volume of Benthic Organisms in Square Foot Samples taken at Station III from October, ........ 1965 through April, 1967 78 18. Composition of Square Foot Bottom Samples taken at Station III from October, 1965 through April, 1967 .....79 19. Composition of the Fish Population Section III of the Green River as indicated by Samples during Fiscal Years 1966 and 1967. (July 1 to June 30 .... 80 20. Number and Volume of Benthic Organisms in Square Foot Samples taken in Section IV from September, 1965 through April, 1967 ........81 91. Composition of Square Foot Samples taken at Station IV from September,1965 through April, 1967 .... 82 92. Number and Volume of Benthic Organisms in Square Foot Bottom Samples taken at Station V from August, 1965 through April, 1967 .... 83 23. Composition of Square Foot Bottom Samples taken at Station V from August, 1965 through April, 1967.0 .. 84 24. Dominant Phyto and Zoo-plankters of the Upper 10 Feet of the Pelagic Zone at Fontenelle Reservoir from August 10, 1965 to May, 1967 .... 85 LIST OF APPENDICES APPENDIX PAGE 1 Fontenelle Reservoir Water Chemistry 9A 2 Fontenelle Reservoir Bottom Fauna 12A 3 Fontenelle Reservoir Plankton 13A 4 Fontenelle Reservoir Fish Condition Factors 17A 5 Green River Water Chemistry 24A 6 Invertebrate Samples, Green River Section 11 27A 7 Invertebrate Samples, Green River Section II 32A 8 Invertebrate Samples, Green River Section III 43A 9 Invertebrate Samples, Green River Section IV 51A 10 Invertebrate Samples, New Fork River 51B ABSTRACT The biota, chemistry and physical regimens of Fontenelle Reservoir and the Green River were sampled from 1965 to 1967. Fontenelle Reservoir was found to be a typical, small, western, alkaline reservoir. When full, the reservoir had a chemical stratification, but no thermocline. Bottom waters of the reservoir were nearly anerobic with relatively high carbon dioxide concentrations. Mougeotia and cladocerans were the principal plankters at that time. Tendipedidae was always the principal bottom organism. After the reservoir was reduced to minimum pool in September, 1965, the chemistry was monotonous and homothermal with only seasonal variations in hydrogen ion (near neutral in winter) and carbon dioxide (high in winter). Oxygen, bicarbonate, and total hardness were comparatively stabile seasonally. Diatoms were the dominant phyto-plankters; while, copepods, rotifers and cladocerans were the dominant zoo-plankters at different times. Several species of aquatic plants (Elodea, Potomogeton and Myriophyllum) became well established in the reservoir shoal areas after draw-down. Rainbow and brown trout comprised about 25 percent of the fish fauna in FY 1967. Salmonid numbers appear to be decreasing, while cyprinids and catostomids apparently are increasing. Gill net catch-per-hour rates increased in FY 1967 for rainbow trout, carp, and flannelmouth suckers. Brown trout and whitefish catch rates decreased. Utah and bonytail chubs were rare in gill net catches. Various small cyprinids and immature cat- ostomids (forage fish) were common in the shoal areas. Gill netted rainbow trout were smaller in FY 1967. Length of rainbow trout at year V was 464 mm; length of brown trout at year VII was 510 mm. Excluding organic debris, midge larvae were the principal item found in rainbow trout stomachs, while scuds and fish were most common in brown trout stomachs. -1- Fontenelle Reservoir greatly influenced its tailwater, the Green River, as a barrier to fish migration, as a factor affecting water temperature and as an artificial control of water flow. Flooding, resulting from the 1965 reservoir draw-down, scoured the river and reduced fish stocks. The fish food and plants apparently recovered within a year of the flood. Downstream from the dam, Tendipedidae was the dominant organism in the post-flood period; bottom fauna population peaks occurred in spring and/or fall. Upstream, the benthic fauna peaked in late fall or winter and was dominated by Tendipedidae or Ephemerella. The Green River was found to be more alkaline and mineral laden downstream from the confluence of the Big Sandy River. The river seems to decrease in productivity below Big Island because of possible marginal summer temperatures, less fish food and poorer trout habitat. The relatively cool river water near Fontenelle Dam may be attracting trout since numbers of rainbow trout decreased drastically downstream from the Big Sandy River and flannelmouth suckers were the most abundant species in FY 1967 samples. The suckers decreased in abundance, while the salmonids remained relatively stabile, in the area between the dam and the Big Sandy River.