US Army Corps of Engineers Rogue Basin Dam Fisheries Evaluation Effects of Lost Creek Dam on the Distribution and Time of Chinoo
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OREGO@ FISH & WILDLIFE REFERENCE LIBRARY US Army Corps of Engineers %Fish & Wilcffilz; Portland District Rogue Basin Dam Fisheries Evaluation Effects of Lost Creek Dam on the Distribution and Time of Chinook Salmon Spawning in the Rogue River Upstream of Gold Ray Dam May 1991 EFFECTS OF LOST CREEK DAM ON THE DISTRIBUTION AND TIME OF CHINOOK SALMON SPAWNING IN THE ROGUE RTVPD 11P1ZTDr'A OF rnin DAv nAM Rogue Basin Fisheries Evaluation Project Research and Development Section Oregon Department of Fish and Wildlife 2501 SW First Street P.O. Box 59 Portland, OR 97207 May 1990 The United States Army Corps of Engineers funded this project under contract DACW57-77-C-0033. CONTENTS Paqe FOREWORD ............................................................... ii SUMMARY 1 ................................................................ Spawning I Distribution ............................................. Spawning Ti 1 ..................................................... RECOMMENDATIONS 2 ........................................................ INTRODUCTION 3 ........................................................... METHODS 4 ........................................ ....................... RESULTS 6 ................................................................ Spawning Distribution 6 ............................................. Spawning Time 10 ..................................................... DISCUSSION 17 ............................................................. ACKNOWLEDGEMENTS 20 ....................................................... REFERENCES 21 ............................................................. APPENDIX A. Tables of Data Relating to Studies of Chinook Salmon 23 ...... APPENDIX B. Figures Showing Annual Relationship Between Location of Carcass Recovery and Date of Tagging 30 ................................... APPENDIX C. Figures Showing Annual Relationship Between Date of Carcass Recovery and Date of Tagging 34 ................................... APPENDIX D. Relation between Gregorian day, day-of-year and week-of-year 38 ........................................................... FOREWORD This report is based on 14 years of research funded by the U.S. Army Corps of Engineers. A study of this duration has necessarily involved the collective effort of many people since its inception in 1974. For this reason, it is being presented as a staff report of personnel on the Rogue Basin Fisheries Evaluation Project. The report was drafted by Thomas Satterthwaite who was largely responsible for the study design and for the analyses contained in the report. Barry McPherson supervised the project and critically reviewed the analyses, conclusions, and recommendations in the final document. Research on the distribution and time of chinook salmon spawning above Gold Ray Dam was in response to concerns by fishery managers on the increased return of fall chinook salmon to spawning areas historically used by spring chinook salmon following the impoundment of water by Lost Creek Dam. The research was primarily an outgrowth of more intensive studies of chinook salmon and steelhead populations that began in the Rogue River in 1973. James Lichatowich was responsible for the original design and guidance of research on anadromous salmonids affected by the operation of Lost Creek Dam. These duties were subsequently assumed by Steven Cramer who served as program leader until 1985. Their leadership and insights on study designs were largely responsible for the ultimate success of research conducted by personnel in the Rogue Basin Fisheries Evaluation Project. The mainstem and tributaries of the Rogue River collectively produce the largest population of wild anadromous salmonids in Oregon. The Rogue River supports recreational and commercial fisheries of immense importance to Oregon citizens and is nationally renowned for its diversity and productivity. Authorizing documents for Lost Creek Dam stipulate that fisheries enhancement is to be an important benefit of the dam, mainly through improved temperature and flow. We hope our studies will ensure that these benefits are achieved for present and future generations of Oregon citizens. Alan McGie Life History Studies Program Leader Research and Development Section Oregon Department of Fish and Wildlife Corvallis, Oregon 14 March 1990 SUMMARY In this report, we evaluate the effect of the operation of Lost Creek Dam on the spawning distribution and the spawning time of chinook salmon Oncorhynchus tshawytscha in the Rogue River upstream of Gold Ray Dam. The Oregon Department of Fish and Wildlife conducted this study because managers became concerned about an increased run of fall chinook salmon to spawning areas historically used by spring chinook salmon. This change was not evident until juveniles produced during postimpoundment years matured and returned to spawn (Satterthwaite 1987). A summarv of our findinas fnllnw-- Spawning Distribution 1. Adults that migrated earliest spawned farthest upstream. 2. Spawning of fall chinook salmon and spring chinook salmon overlapped in the area between Trail Creek and the pool behind Gold Ray Dam. Few fall chinook salmon, but many spring chinook salmon, spawned upstream of Trail Creek. We 3. did not detect any change in the spawning distribution of fall chinook salmon, possibly because we sampled few adults that originated from preimpoundment broods. 4. Spring chinook salmon broods produced after full operation began at Lost Creek Dam spawned farther downstream compared with preimpoundment broods. A 5. decrease in the relative abundance of early migrating adults, compared with late migrating adults, was responsible for the downstream shift in the spawning distribution of spring chinook salmon. 6. Increased water temperature during the period eggs and alevins incubated in the gravel, or increased harvest rate within the sport fishery upstream of Gold Ray Dam, may have decreased the relative abundance of early migrants among wild spring chinook salmon that returned to the Rogue River. Spawning Time 1. Adults that migrated earliest spawned earliest. 2. Fall chinook salmon excavated few redds of spring chinook salmon, but probably interbred with the spring race. In the area where spawning of fall and spring races overlapped, spawning time differed little between races. 3. Spring chinook salmon broods produced after full operation began at Lost Creek Dam spawned later compared with preimpoundment broods. Time of spawning did not change among cohorts of hatchery origin. 4. The change to later spawning was most pronounced for early migrating spring chinook salmon. Late migrating adults were less affected. I 5. Spawning time correlated with water temperature when eggs and alevins incubated in the gravel. Adults spawned later when broods were exposed to increased incubation temperatures. Spawning time was not correlated with river physical parameters during spawning. 6. Later spawning of wild spring chinook salmon that originated from postimpoundment broods was probably the result of decreased survival rate among progeny of early spawning adults. Increased harvest rate within the sport fishery upstream of Gold Ray Dam may have also decreased the relative abundance of early spawning adults. RECOMMENDATIONS 1. The evaluation of modified strategies of water temperature released from Lost Creek Dam should be completed. Decreased outflow temperature during autumn may increase the abundance of wild spring chinook salmon that migrate (and spawn) early in the season. Decreased outflow temperature may also decrease the proportion of fall chinook salmon among wild chinook salmon that spawn upstream of Gold Ray Dam. 2. Spawned carcasses should be surveyed annually in the mainstem between Cole M. Rivers Hatchery and Shady Cove, and in Big Butte Creek, as part of a long-term management program for spring chinook salmon in the Rogue River basin. Any significant changes in spawning time should be further evaluated by replicating the study described in this report. Also, data from these surveys can be used to estimate the spawning escapement of wild spring chinook salmon. The estimated run of adults at Gold Ray Dam is not a reliable estimate of spawning escapement of wild fish because (1) unmarked hatchery fish compose a large portion of the run and (2) harvest and prespawning mortality of wild fish above Gold Ray Dam is not accurately estimated. 3. The migration time of wild and hatchery spring chinook salmon should be estimated annually at Gold Ray Dam as part of a long-term management program for spring chinook salmon in the Rogue River basin. Estimates of migration timing can be developed by scale analysis or by an expanded program of marking juveniles at Cole M. Rivers Hatchery. Analysis of scales would probably require extensive sampling at Gold Ray Dam, possibly as many as 200 adults every 2 weeks. A better option might be to mark a constant proportion of the release groups with fin clips. Based on the findings of Hankin (1982), we recommend a minimum mark rate of 25%. The marking rate should be constant between years and between release groups. Also, the selected mark should be visible as adults pass the counting station at Gold Ray Dam. 4. Efforts to enhance the production of spring chinook salmon should concentrate on the restoration of the early migrating component of the wild stock. Early migrants contribute to the river fisheries at a higher rate than late migrants. Wild fish also contribute at a higher rate than hatchery fish to the fishery upstream