REGIONAL INFORMATION REPORT 3A97-35 Alaska Department of Fish and Game Commercial Fisheries Management and Development Division 333 Raspberry Road Anchorage, Alaska 99518 October 1997 Salmon Escapement Assessment in the Toklat River, 1994 by Louis H. Barton State ofAlaska Tony Knowles, Governor SALMON ESCAPEMENT ASSESSMENT IN THE TOKLAT RIVER, 1994 By Louis H. Barton Regional Information Report) No. 3A97-35 Alaska Department ofFish and Game Commercial Fisheries Management and Development Division, AYK Region 333 Raspberry Road Anchorage, Alaska 99518-1599 October 1997 lThe Regional Information Report Series was established in 1987 to provide an information access system for all unpublished divisional reports. These reports frequently serve diverse ad hoc informational purposes or archive basic uninterpreted data. To accommodate timely reporting and recently collected information, reports in this series undergo only limited internal review and may contain preliminary data; this information may be subsequently ftnalized and published in the formal literature. Consequently, these reports should not be cited without prior approval of the author or the Commercial Fisheries Management and Development Division. The Alaska Department of Fish and Game operates all of its public programs and activities free from discrimination on the basis or race, religion, color, national origin, sex or handicap. Because the department receives federal funding, any person who believes he or she has been discriminated against should write to: D.E.C., U.S. Department ofInterior, Washington, D.C. 20204. ii AUTHOR Louis H. Barton is the fall chum and coho salmon Yukon Area Research Biologist for the Alaska Department of Fish and Game, Commercial Fisheries Management and Development Division, 1300 College Road, Fairbanks, AK 99701. ACKNOWLEDGMENTS Special thanks are extended to those who participated in this project and who are largely responsible for its success: K. Boeck and O. Wear. Critical review of this report was provided by L. Buklis, J. Bromaghin, and D. Huttunen. SPONSORSIDP This project was partially funded by Yukon River Salmon US./Canada Negotiation Studies, grant Award No. NA46FP0343 from the US. Department ofCommerce. iii TABLE OF CONTENTS LIST OF TABLES vi LIST OF FIGURES vii LIST OF APPENDICES .ix ABSTRACT u •••••••••••••••••••••••••••••••••••••••••••••••x INTRODUCTION 1 Study Area 3 Toklat River Basin 3 Toklat Springs 3 Barton Creek 4 Objectives 4 METHODS 5 Hydroacoustic Equipment and Site Selection 5 Sonar Calibrations and Count Adjustments 6 Barton Creek Weir 8 Climatological and Hydrological Observations 8 Spawning Ground Surveys and Population Estimate 8 RESULTS 9 River and Sonar Counting Conditions 9 Abundance Estimation l 0 Temporal and Spatial Distribution 11 Weir Passage 12 Spawning Ground Surveys - Toklat Springs 13 iv TABLE OF CONTENTS Page DISCUSSION 14 LITERATlTRE CITED 16 TABLES 18 FIGURES 24 APPENDIX 40 v LIST OF TABLES 1. Alaskan and Canadian total utilization ofYukon River fall chum salmon, 1961- 1994 18 2. Toklat River fall chum salmon total spawning abundance estimates based upon surveys ofthe spawning area at Toklat Springs, 1974-1993 19 3. Estimated steam life curve (SLC) and migratory time density curve (MTDC) for Toklat River fall chum salmon based upon Delta River studies 20 4. Sonar-estimated fish passage in the Toklat River, 1994 21 5. Daily chum and coho salmon passage at Barton Creek weir (Toklat River drainage), 1994 22 6. Abundance and distribution ofchum and coho salmon at Toklat Springs based upon ground surveys conducted in mid-October 1994 23 vi LIST OF FIGURES 1. Important Yukon River fall chmn salmon spawning areas 24 2. The Tanana River drainage 25 3. The Toklat River drainage 26 4. That portion ofthe Toklat River known as Toklat Springs 27 5. The Toklat River and Barton Creek terminus 28 6. Toklat River sonar site and Barton Creek weir location, 1994 29 7. Schematic ofprefabricated transducer pod using 1-1/2 in (3.8 cm) and 3/4 inch (1.9 cm) galvanized water pipe 30 8. Main channel depth profiles made at the Toklat River sonar project site in August 1993 and 1994 31 9. Daily water levels observed in the main channel Toklat River at the sonar project site, 1994 32 1O. Average daily percent calibration effort versus average daily percent fish passage along the left bank (top) and right bank (bottom) in the Toklat River, 1994 33 11. Daily sonar fish passage estimates (by bank) in the Toklat River, 1994 34 12. Estimated average proportion offish passing the Toklat River project site by electronic sector, 1994 35 13. Average temporal migration pattern offish passing the Toklat River sonar project site, 1994 36 14. Downstream view(s) ofToklat Springs, 27 September 1994 37 15. Salmon counts made during ground surveys ofSushana River, Geiger Creek, and selected floodplain sloughs ofToklat Springs, October 1994 38 vii LIST OF FIGURES Figure Page 16. Salmon counts made during ground surveys ofselected floodplain sloughs of Toklat Springs, October 1994 39 viii LIST OF APPENDICES Appendix APPENDIX A: TOKLAT RIVER mSTORIC CHUM SALMON GROUND SURVEY DATA A.l. Fall chum salmon survey observations and expanded escapement estimates for Toklat River floodplain sloughs within the index area known as Toklat Springs, 1974-1993. The portion ofthe floodplain included extends from approximately 0.5 kIn upstream to 2.0 kIn downstream ofKnight's Roadhouse 41 A.2. Fall chum salmon survey observations and expanded escapement estimates for Geiger Creek, 1974-1993 43 A.3. Fall chum salmon survey observations and expanded escapement estimates for Sushana River, 1974-1993 45 A.4. Percent live chum salmon observed from ground surveys conducted at Toklat Springs, 1976-1993. Numbers in parentheses represent year ofsurvey .47 APPENDIXB: TOKLAT RIVER CLIMATOLOGICAL AND HYDROLOGIC OBSERVATIONS B.l. Climatological and hydrologic observations made at the Toklat River sonar project site, 1994 49 APPENDIXC: TOKLAT RIVER SONAR CALIBRATION DATA C.l. Oscilloscope data used to calibrate the left bank sonar counter at the Toklat River project site, 1994 53 C.2. Oscilloscope data used to calibrate the right bank sonar counter at the Toklat River project site, 1994 58 APPENDIXD: TOKLATRIVERTEMPORALSONARCOUNTDATA D.l. Temporal distribution ofdaily sonar counts along the left bank Toklat River, 1994 61 D.2. Temporal distribution ofdaily sonar counts along the right bank Toklat River, 1994 64 ix ABSTRACT A sonar-estimated escapement of 75,867 salmon was obtained for the Toklat River upstream of Barton Creek for the period 14 August through 4 October 1994. Eighty-nine percent of the estimated passage was along the left bank and 11 % along the right bank. The mode and median day ofpassage both occurred on 21 September. Approximately, 99% ofthe sonar estimate (75,108) was apportioned to fall-run chum salmon Oncorhynchus keta with the remainder considered as coho salmon 0. kisutch. Apportionment was based upon species composition observed during ground surveys of the major spawning area at Toklat Springs in mid-October. Although this passage estimate is considered conservative due to an unknown number of salmon which passed the sonar counting site prior and subsequent to counting operations, it compares exceptionally well with the total abundance estimate of 76,057 chum salmon made from intensive ground surveys of Toklat Springs during peak of spawning. An additional 39 chum and approximately 2,000 coho salmon passed Barton Creek weir during the same period (mid-August through early October), in addition to three chinook salmon 0. tshawytscha. Variations in water levels and velocities, together with migration behavior of upstream migrant Toldat River salmon, affected the ability of the hydroacoustic equipment to accurately estimate salmon passage. However, this factor was addressed by adjusting fish passage estimates as necessary based upon daily calibrations ofthe hydroacoustic equipment. Sonar counting range was considered adequate for the detection of the majority of fish passing the sonar site as most were oriented nearshore. Daily passage was greatest during periods of darkness, with the greatest movement occurring on the average between 2200 and 2400 hours. KEY WORDS: Chum salmon, Coho salmon, Oncorhynchus keta, 0. Kisutch, hydroacoustics, sonar, escapement, Yukon River, Tanana River, Kantishna River, Toklat River x INTRODUCTION Although five species of Pacific salmon Oncorhynchus are found in the Yukon River drainage, chum salmon 0. keta are the most abundant and occur in genetically distinct summer and fall runs (Wilmot et al. 1992; Seeb et al. 1995). Fall chum salmon are larger, spawn later, and are less abundant than their summer chum counterpart. They primarily spawn in the upper portion of the drainage in streams which are spring fed, usually remaining ice-free during the winter (Buklis and Barton 1984). Major fall chum salmon spawning areas include the Tanana, Chandalar, and Porcupine River systems, as well as selected Canadian portions ofthe Yukon River (Figure 1). Fall chum salmon are harvested commercially along the entire mainstem Yukon River in Alaska as well as in the Canadian portion of the river near Dawson, Y.T. Commercial harvest is also permitted in the lower portion of the Tanana River in Alaska, but no commercial fishing is permitted in other tributaries, including the Koyukuk and Porcupine River systems. While the majority of commercially taken fish come from the lower river, downstream of the village of Anvik, fall chum salmon