Fishery Data Series No. 95-41 Assessment of the 1994 Return of Steelhead to the Karluk River, Alaska bY Robert N. Begich December 1995 Alaska Department of Fish and Game Division of Sport Fish FISHERY DATA SERIES NO. 95-41 ASSESSMENT OF THE 1994 RETURN OF STEELHEAD TO THE KARLUK RIVER, ALASKA Robert N. Begich Division ofsport Fish, Kodiak Alaska Department of Fish and Game Division of Sport Fish, Research and Technical Services 333 Raspberry Road, Anchorage, Alaska, 995 18-1599 December 1995 This investigation was partially financed by the Federal Aid in Sport Fish Restoration Act (16 U.S.C. 777-777K) under Project F-10-10, Job No. R-2-7. The Fishery Data Series was established in 1987 for the publication of technically-oriented results for a single project or group of closely related projects. Fishery Data Series reports are intended for fishery and other technical professionals. Distribution is to state and local publication distribution centers, libraries and individuals and, on request, to other libraries, agencies, and individuals. This publication has undergone editorial and peer review. Robert N. Begich Alaska Department of Fish and Game, Division of Sport Fish, 21 I Mission Road, Kodiak, Alaska, 99615-6399, USA This document should be cited as: Begich, Robert N. 1995. Assessment of the 1994 return of steelhead to the Karluk River, Alaska. Alaska Department of Fish and Game, Fishery Data Series No. 95-41, Anchorage. The Alaska Department of Fish and Game administers all programs and activities free from discrimination on the basis of sex, color, race, religion, national origin, age, marital status, pregnancy, parenthood, or disability. For information on alternative formats available for this and other department publications, contact the department ADA Coordinator at (voice) 907-465-4120, or (TDD) 907-465-3646. Any person who believes s/he has been discriminated against should write to: ADF&G, PO Box 25526, Juneau, AK 99802-5526; or O.E.O., U.S. Department of the Interior, Washington, DC 20240. TABLE OF CONTENTS Page LIST OF TABLES . ................................ ii LIST OF FIGURES . ............................. iii LIST OF APPENDICES . ....................... iv ABSTRACT . .......................................... 1 INTRODUCTION . ................................. 1 ESTIMATION OF STEELHEAD BYCATCH IN SELECTED COMMERCIAL FISHERIES . 5 Methods ......................................................................................................................................................................... 5 Set Gillnet Fishery .................................................................................................................................................... 8 Tender-Sampled Set Gillnet and Purse Seine Fishery ............................................................................................. .9 Results ......................................................................................................................................................................... 10 ESTIMATION OF STEELHEAD HARVEST IN THE KARLUK RIVER SUBSISTENCE FISHERIES ................ 15 Methods ....................................................................................................................................................................... 15 Results ......................................................................................................................................................................... 19 ESTIMATION OF STEELHEAD HARVEST IN THE KARLUK RIVER SPORT FISHERY ................................. 19 Methods ....................................................................................................................................................................... 19 Results ......................................................................................................................................................................... I9 ESTIMATION OF SPAWNING ABUNDANCE AND SURVIVAL.. ...................................................................... .23 Methods ......... .............................................................................................................................................................. 23 Abundance .............................................................................................................................................................. 23 Age and Length Composition ................................................................................................................................. 25 Spawning Survival .................................................................................................................................................. 26 Results ......................................................................................................................................................................... 26 Abundance .......... .................................................................................................................................................... 26 Biological Composition of the Spawning Population ............................................................................................. 29 Spawning Survival .................................................................................................................................................. 29 DISCUSSION .............................................................................................................................................................. 29 ACKNOWLEDGMENTS . ................... 47 LITERATURE CITED . ........................ 52 APPENDIX A. LENGTH-AT-AGE DATA FOR STEELHEAD FROM THE KARLUK RIVER STUDY AREA, 1994 . .............. 55 APPENDIX B. AYAKULIK RIVER STEELHEAD LENGTH-AT-AGE AND SPAWNING HISTORIES, 1995 . ........................... 61 i LIST OF TABLES Table Page 1. Estimated harvest of steelhead retained for personal use in commercial set gillnets near the Karluk River, August 15 through September 30, 1994. ........................................................................................... .I 1 2. Estimated release of steelhead from commercial set gillnets near the Karluk River, August 15 through September 30, 1994. ...................................................................................................................................... 12 3. Estimated harvest of steelhead from tender sampled commercial set gillnet catches, near the Karluk River, August 15 through September 30, 1994. ........................................................................................... .I3 4. Estimated harvest of steelhead from tender sampled commercial purse seine catches, near the Karluk River, August 15 through September 30, 1994. ............................................................................................ 14 5. Steelhead retained for personal use or released from the set gillnet fishery by statistical area and sampling strata, August 15 through September 30, 1994.. ........................................................................... .16 6. Length-at-age by spawning history and sex of steelhead harvested by commercial set gillnets and purse seines near the Karluk River, August 15 through September 30, 1994.. ...................................................... .17 7. Age composition by sex and spawning history of steelhead harvested by commercial set gillnets and purse seines near the Karluk River, August 15 through September 30, 1994. ............................................. .18 8. Subsistence harvest of steelhead by residents of Karluk Village, since 1982. ............................................. .20 9. Subsistence harvest of steelhead by residents of Larsen Bay, since 1982.. .................................................. .2 1 10. Sport harvest and release of steelhead and total fishing effort from the Karluk River sport fishery, 1982-1994. .................................................................................................................................................... 22 11. Length-at-age by spawning history and sex of steelhead harvested by the Karluk River sport fishery, October 4 through November 11, 1994. ....................................................................................................... .24 12. Summary of tagging data for steelhead released at the Portage and recaptured at the Karluk weir, Karluk River, 1995. ....................................................................................................................................... 27 13. Sex composition by week of emigrating steelhead Karluk River, 1995.. ..................................................... .30 14. Age composition, by sex, of spawning steelhead trout in the Karluk River, April 1994. Based on hook and line captures of the spawning population. ............................................................................................. .32 15. Length-at-age by spawning history and sex of hook and line captures of the spawning population of the Karluk River, April 1995.. ...................................................................................................................... .34 16. Age composition by spawning history and sex of steelhead emigrating through the Karluk River weir, May 15 through July 3 1, 1995. .................................................................................................................... .35 17. Length-at-age