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Use of Hydroacoustics to Examine Spatial and Temporal Patterns of Pacific Salmon

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Use of Hydroacoustics to Examine Spatial and Temporal Patterns of Pacific Salmon USE OF HYDROACOUSTICS TO EXAMINE SPATIAL AND TEMPORAL PATTERNS OF PACIFIC SALMON (ONCORHYNCHUS SPP.) BEHAVIOR DURING SPAWNING MIGRATIONS IN NUSHAGAK RIVER, ALASKA. A Thesis Presented to the Faculty of Alaska Pacific University In Partial Fulfillment of the Requirements For the Degree of Master of Science in Environmental Science By Samantha C. Simpson April 2014 UMI Number: 1555183 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. UMI 1555183 Published by ProQuest LLC (2014). Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, MI 48106 - 1346 ii I grant Alaska Pacific University the non-exclusive right to use this work for the purpose of making single copies available to the public on a not-for-profit basis if the University’s circulating copy is lost or destroyed. ____________________________________ Samantha Simpson Date________________________________ iii USE OF HYDROACOUSTICS TO EXAMINE SPATIAL AND TEMPORAL PATTERNS OF PACIFIC SALMON (ONCORHYNCHUS SPP.) BEHAVIOR DURING SPAWNING MIGRATIONS IN NUSHAGAK RIVER, ALASKA. by Samantha C. Simpson THESIS APPROVED: Thesis Committee _____________________________ ________________ Chairperson Date Bradley Harris, Ph.D. Assistant Professor Alaska Pacific University _____________________________ ________________ Thesis Committee Date Gregory Buck Assistant Area Research Biologist, Bristol Bay Alaska Department of Fish and Game _____________________________ ________________ Thesis Committee Date Roman Dial, Ph.D. Assistant Professor Alaska Pacific University APPROVED: _____________________________ ________________ Tracy Stewart, Ph.D. Date Academic Dean Alaska Pacific University i ACKNOWLEDGEMENTS I am deeply indebted to my committee members, Drs. Bradley Harris and Roman Dial, and Gregory Buck for their persistent guidance, expertise, and encouragement throughout this process. I cannot find words to express my sincere gratitude for my advisor, Dr. Harris, for energetically accepting me as his first graduate student upon his arrival at APU, and his continued and convincing excitement about my project, especially when things seemed hopeless to me. I am grateful for his ideas and positive outlook on the project, as well as all the hours spent on my thesis development and review. Thank you for being so easy and enjoyable to work with. I am tremendously grateful for all the feedback and statistics instruction received from Dr. Dial, and his expertise raised the content of this thesis. While my journey on this thesis is complete, I would not have arrived here if it wasn’t for the Alaska Department of Fish and Game and Greg Buck. His exclusive knowledge of Nushagak River salmon, anadromous fish ecology, and fisheries management in Alaska made for worthwhile application of this thesis. The Alaska Department of Fish and Game provided invaluable support specifically in the early stages of this project, and I would like to thank Jeff Regnart, Tim Baker, Lowell Fair, Suzanne Maxwell, and April Faulkner for their guidance and expertise, in addition to the Nushagak River sonar crews who keep the DIDSON project running successfully, year after year. I am very fortunate to have a wonderful group of colleagues who assisted in the completion and review of this thesis, from both the fisheries lab at APU and in my professional career. Nick Tucker of APU played a vital role in getting echograms ii processed and worked at incredible speeds, and Sarah Webster and Jenipher Cate conducted expeditious and careful peer reviews of my work. Bill Hanot and Sergio da Costa, of Soundmetrics Corp., provided considerable technical support when DIDSON questions arose. Thank you all for contributing your valuable time to enhance this project. I am very thankful for the education I have received from both my undergraduate and graduate institutions, and must also thank Dr. Ana irovi for getting me started in the graduate program at APU and encouraging me to develop a project within my personal interests. I would not have found myself in this program without recognizing my love for Alaska and its fascinating environment; Mitch Osborne, Ray Hander, and Theresa Tanner helped me to come to this realization early on in my fisheries career and have provided moral support throughout the duration of this thesis. I truly have an incredible group of friends, coworkers, and even some acquaintances who have constantly reminded me over the past several years to get my thesis completed (you know who you are). Words cannot describe the positive influence that your persistent badgering has had on me. Thank you all for listening to my thesis quandaries whether it was at our hockey games, while out on runs, or over a few adult beverages. Additionally, moral support and encouragement from RJM and BRW were indispensable. Thank you. Last but not least, I owe immeasurable gratitude to my parents, Jeff and Lori, and brother, Jay, for their love and everlasting support of my goals. iii ABSTRACT The Nushagak River, Bristol Bay, Alaska, supports one of the largest wild sockeye salmon (Oncorhynchus nerka) runs in the state and also supports overlapping runs of chum (O. keta) and Chinook (O. tshawytscha) salmon. Each summer, the Alaska Department of Fish and Game deploys dual-frequency identification sonar (DIDSON) on the river to enumerate salmon to monitor escapement goals; however, salmon behavior and spawning run characteristics at the site are not incorporated into management. We investigated the feasibility of using Nushagak River DIDSON data from 2008-2011 to identify trends in run timing and compare passage rates to local environmental conditions, including tide, light intensity, and water temperature. We also used spatial analysis to examine aggregation behavior of salmon at the DIDSON site at multiple distance scales. Between all four years, run timing only varied within a few days (< 1 week), regardless of water temperature. In 2009 and 2011, more salmon passed upriver during slack and ebb tides than during flood tide. Salmon were never completely spatially random, and distance scales of aggregation behavior were influenced by run period and photo period. When examining all factors together, the interaction between salmon density and run period affected distance at maximum aggregation. This research used hydroacoustics for a multi-level approach to investigating spatiotemporal patterns of Pacific salmon relative to environmental factors during their spawning migration and may help refine in-season monitoring and management of the fishery. iv TABLE OF CONTENTS ABSTRACT .................................................................................................................................... iii LIST OF FIGURES ........................................................................................................................ vi LIST OF TABLES ........................................................................................................................ viii GENERAL INTRODUCTION ........................................................................................................ 1 CHAPTER 1 .................................................................................................................................... 5 1.1 INTRODUCTION ..................................................................................................................... 6 1.2 METHODS ................................................................................................................................ 9 Site Description ............................................................................................................................ 9 DIDSON Recording ................................................................................................................... 11 Species Apportionment .............................................................................................................. 13 Light Intensity ............................................................................................................................ 13 Temperature ............................................................................................................................... 16 Tide ............................................................................................................................................ 16 1.3 RESULTS ................................................................................................................................ 18 Light Intensity ............................................................................................................................ 20 Temperature ............................................................................................................................... 27 Tide ............................................................................................................................................ 31 1.4 DISCUSSION .........................................................................................................................
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