DOCSLIB.ORG

Coho Salmon Life History Patterns in the Pacific Northwest and California

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Coho Salmon Life History Patterns in the Pacific Northwest and California Coho Salmon (Oncorhynchus kisutch) Life History Patterns in the Pacific Northwest and California Final Report March 2007 Prepared for U.S. Bureau of Reclamation Klamath Area Office Prepared by Lawrence C. Lestelle 17791 Fjord Drive NE Suite AA Poulsbo, WA 98370 360-697-6702 ACKNOWLDGEMENTS This project was funded by the U.S. Bureau of Reclamation (USBR). Ron Costello, Richard Piaskowski, and Cindy Williams of the Klamath Area Office were particularly helpful in securing funding and coordinating field visits to Klamath area streams. Steve Cramer, Nick Ackerman, and Tom Nickelson of Cramer Fish Sciences provided insightful reviews of early drafts and shared information sources. Josh Strange with the Yurok Fisheries Program of the Yurok Tribe provided helpful comments on the review draft, as did Jim Simondet of the Arcata Area Office of NOAA Fisheries. Special thanks are due to the five scientists who kindly responded to an invitation from USBR to give technical peer review of the report. Each of these individuals are experts on coho life history and have first-hand experience in researching this species in different geographic areas. These are Walt Duffy, Humboldt State University, James Hall, Oregon State University (retired), Gordon Hartman, Department of Fisheries and Oceans Canada (retired), Peter Moyle, University of California at Davis, and Tom Quinn, University of Washington. Tom Nickelson, previously mentioned for his review, deserves to be ranked with this distinguished group for his expertise on coho life history. Coho Salmon Life History Patterns i Table of Contents ACKNOWLDGEMENTS .................................................................................................. i Table of Contents.......................................................................................................... ii List of Figures .............................................................................................................. iii List of Tables ................................................................................................................ ix Executive Summary ..................................................................................................... xi 1.0 Introduction ............................................................................................................. 1 2.0 Life History Overview.............................................................................................. 3 2.1 Distribution Patterns ............................................................................................................ 3 2.2 Life Cycle Overview and Unique Characteristics................................................................ 7 3.0 Freshwater Habitat Utilization.............................................................................. 28 3.1 Description of Channel and Habitat Types ........................................................................ 28 3.2 Life Stage-Specific Habitat Utilization and Survival......................................................... 36 3.2.1 Spawning Migration................................................................................................... 36 3.2.2 Spawning.................................................................................................................... 38 3.2.3 Egg and Alevin Incubation......................................................................................... 39 3.2.4 Fry Colonization......................................................................................................... 46 3.2.5 Subyearling Summer Rearing .................................................................................... 49 3.2.6 Fall Redistribution and Overwintering....................................................................... 65 3.2.7 Smolt Migration ......................................................................................................... 83 4.0 Discussion and Conclusions ............................................................................... 93 Literature Cited.......................................................................................................... 100 Coho Salmon Life History Patterns ii List of Figures Figure 1. The spawning distribution of Pacific salmon in a hypothetical watershed. Typical distribution of chum (a), pink (b), coho (c), Chinook (d), and sockeye (e). From Lichatowich (1999)............................................................................................................. 5 Figure 2. Salmonid usage zones in the Clearwater River (Olympic Peninsula, Washington) delineated by predominate species. From Edie (1975). Distribution patterns in this river reflect those that commonly occur for these species in the Pacific Northwest and California. ........................................................................................................................... 6 Figure 3. Oceanic distribution patterns of coho salmon originating in California, Oregon, Washington, and British Columbia. From Wright (1968). ................................................. 7 Figure 4. Utilization pattern by coho salmon of different areas of the Clearwater River (Olympic Peninsula, Washington) by life stage. Circle size reflects the relative amounts of production attributed to each area. Dashed lines show movements of fish from one area (dot) to another area (arrow). From Lestelle et al. (1993a). The chart illustrates the extent that coho juveniles can move during freshwater life to locate suitable habitats................................................................................................................... 9 Figure 5. Representative pattern of movement and migration of juvenile coho salmon seen in many streams across the species’ geographic range. Created from data in Au (1972) for Deer Creek, Alsea River system (Oregon Coast)........................................................ 10 Figure 6. Movement of juvenile coho salmon past trap site in the South Fork Umpqua River (Oregon Coast) during spring and summer. Pattern is stylized from data in Kruzic (1998). Movement of juveniles during summer is believed due to high water temperatures...................................................................................................................... 10 Figure 7. Marine survival from smolt to 3-year old ocean recruitment for wild coho originating in rivers of the Puget Sound and Washington outer coastal regions. Populations representing the two regions are Big Beef Creek and Bingham Creek for Puget Sound and WA coast, respectively. Data from Volkhardt et al. (2007). ................ 13 Figure 8. Juvenile coho salmon (top), Chinook salmon (middle), and steelhead trout (bottom) illustrating differences in fin size and body morphology. Photos courtesy of Roger Tabor, U.S. Fish and Wildlife Service, Lacey, Washington. Note that the dorsal and anal fins of the coho are easily recognized by their white leading edges......................... 17 Figure 9. Diagrammatic sketches of the dorsal and anal fins of recently emerged and 2-week old coho and fall Chinook salmon in Sixes River (Oregon Coast). From Stein et al. (1972). Note that differences in size of fins between species increase as fish grow (see Figure 10) and appear to be greatest at lengths of about 60 mm, which for coho would typically occur between mid to late summer. ................................................................... 18 Figure 10. Differences in dorsal and anal fin sizes between juvenile coho and Chinook salmon. From Stein et al. (1972)....................................................................................... 19 Figure 11. Water depth and velocity preferences of coho salmon, Chinook salmon, and steelhead trout fry (<50 mm) and parr (>50 mm), as observed in the Trinity River in the Klamath River basin (Northern California). Water velocities are mean column values. Adapted from Hampton (1988). ........................................................................... 20 Coho Salmon Life History Patterns iii Figure 12. Water depth and velocity preferences of subyearling coho salmon found in rivers of Western Washington. From Beecher et al. (2002). Water velocities are measured at 0.6 depth (approximately equal to mean water column values). Note: 30.5 cm = 1 ft..... 21 Figure 13. Coastal coho foraging phenotypes, showing unique growth rate cycles and movement from fresh water to the stream mouth estuary, as documented in Northern California streams. Presence within the stream mouth estuary is shown as shaded. Adapted from Nielsen (1992a).......................................................................................... 25 Figure 14. Riverine habitat types utilized by salmonid species. From Lestelle et al. (2005) with revision to use of the term “alcove” – see text. In channel mesohabitats occur in the main channel, side channels, and braids. .................................................................... 29 Figure 15. Illustration from Beechie et al. (2005) showing example of locations of habitat units delineated on the Skagit River (Washington). Note the very large backwater unit. Backwater units were most commonly located where off-channels or side channels joined the main river. See Figure 16 for photograph of the backwater shown in this figure................................................................................................................................. 30 Figure 16. Backwater habitat unit on the Skagit
Load more

Recommended publications
  • Agenda Item L
    Kate Brown, Governor 775 Summer Street NE, Suite 360 Salem OR 97301-1290 www.oregon.gov/oweb (503) 986-0178 Agenda Item L supports OWEB’s Strategic Plan priority # 6: Coordinated Monitoring and Shared Learning. MEMORANDUM TO: Oregon Watershed Enhancement Board FROM: Audrey Hatch, Conservation Outcomes Coordinator Renee Davis, Deputy Director SUBJECT: Agenda Item L – Telling the Restoration Story January 22-23, 2020 Board Meeting I. Introduction “Telling the Restoration Story” is a targeted grant offering that helps OWEB and grantees better communicate the ecological outcomes of restoration funded by OWEB. These grants support compilation, analysis, and/or interpretation of existing data from a watershed restoration project, and production of outreach materials that describe outcomes. Outreach products will reach a broad audience, including board members and legislators. Grantees also have identified specific audiences, so their messages about factors that lead to quantifiable restoration success will have high impact by speaking to landowners, restoration practitioners, and natural resource managers working to restore similar landscapes in Oregon. II. Progress to Date Seven projects were funded by OWEB in 2019: 1. Smith River Watershed Council: video, two-page fact sheet and technical report about how stream restoration treatments have increased salmon populations in the West Fork Smith River; 2. Lake County Umbrella Watershed Council: video, four-page fact sheet and technical report that highlights how fish passage projects benefit sensitive species in the Warner Lakes Basin; 3. Rogue Basin Partnership: online story map, fact sheet and compilation of fish passage restoration projects in the Rogue Basin; 4. Coos Watershed Association: video, fact sheet, and update to previously developed Willanch Creek report that details how riparian restoration improved habitat and helped keep water temperatures cool; 5.
    [Show full text]
  • Umpqua Bibliography by Groups I. Possible
    Umpqua Bibliography by Groups Introduction This bibliography is about the Umpqua River Basin, particularly its hydrology and its fisheries. Some films, photographs and archival materials are included along with books, articles, maps and web pages. The bibliography was built using local, regional and national library catalogs, major online databases, theses and dissertations, watershed assessments and Federal endangered species reports. Its historical coverage begins with Joel Palmer’s 1847 Journal of Travels over the Rocky Mountains and ends in early 2008. I have attempted to cover major physical features of the Umpqua Basin, as well as important aquatic species and critical issues facing the area. Trying to build a comprehensive collection of references on any subject in the age of information is, to use an image Joel Palmer would understand, like trying to catch a greased pig. It is ever squirming out of your grasp. This collection of references is necessarily incomplete, but I’d be grateful to learn of any major omissions. --Susan Gilmont Updated September, 2008 I. Possible Candidates for Digitization: Grey Literature, Important Or Uncataloged Reports on the Umpqua River (Sorted by Date) Roth, A. R. A survey of the waters of the South Umpqua Ranger District : Umpqua National Forest . Portland, Or.: USDA Forest Service, Pacific Northwest Region; 1937. Call Number: OSU Libraries: Valley SH35.O7 U65 Notes: Baseline temperature data for the Umpqua Oregon State Game Commission. Lower Umpqua River Study : Summary : Annual Report. 1949. Call Number: Available from NMFS Environmental and Technical Svcs. Division, 525 NE Oregon St. Portland, OR 97232 (? dated reference). State Library or StreamNet should have this.
    [Show full text]
  • CURRICULUM VITAE University of Idaho
    CURRICULUM VITAE University of Idaho NAME: Madison S. Powell DATE: January 5, 2018 RANK OR TITLE: Associate Professor, Department of Animal and Veterinary Science Associate Director, Aquaculture Research Institute, Hagerman Fish Culture Experiment Station DEPARTMENT: Animal and Veterinary Science OFFICE LOCATION AND CAMPUS ZIP: OFFICE PHONE: 208-837-9096 FAX: 208-837-6047 Hagerman Fish Culture Experiment Station EMAIL: [email protected] 3059F National Fish Hatchery Road Hagerman, ID 83332 DATE OF FIRST EMPLOYMENT AT UI: June 1995 DATE OF TENURE: Tenured July 2008 DATE OF PRESENT RANK OR TITLE: July 2008 EDUCATION BEYOND HIGH SCHOOL: Degrees: Ph.D., Texas Tech University, Lubbock, TX, Zoology, 1995 M.S., University of Idaho, Moscow, ID, Zoology, 1990 B.S., University of Idaho, Moscow, ID, Zoology and Biology, 1985 EXPERIENCE: Teaching, Extension and Research Appointments: Associate Professor / Graduate Faculty, Bioinformatics and Computational Biology Faculty, Department of Animal and Veterinary Science, Aquaculture Research Institute, Hagerman Fish Culture Experiment Station, University of Idaho, Hagerman, Idaho, 2008 – present Assistant Professor / Graduate Faculty, Department of Animal and Veterinary Science, Aquaculture Research Institute, Hagerman Fish Culture Experiment Station, University of Idaho, Hagerman, Idaho, 2002 – 2008 Research Assistant Professor, Department of Animal and Veterinary Science / Department of Fish and Wildlife Resources, Aquaculture Research Institute, Hagerman Fish Culture Experiment Station, University
    [Show full text]
  • 1992 Annual Report
    THE OREGON PLAN for Salmon and Watersheds Status of Oregon Coastal Stocks of Anadromous Salmonids, 2000-2001 and 2001-2002 Report Number: OPSW-ODFW-2002-3 Status of Oregon Coastal Stocks of Anadromous Salmonids, 2000-2001 and 2001-2002 Oregon Plan for Salmon and Watersheds Monitoring Report No. OPSW-ODFW-2002-3 September, 2002 Steven Jacobs Julie Firman Gary Susac David Stewart Jared Weybright Coastal Salmonid Inventory Project Western Oregon Research and Monitoring Program Oregon Department of Fish and Wildlife 28655 Highway 34 Corvallis, OR 97333 Funds supplied in part by: Sport Fish and Wildlife Restoration Program administered by the U.S. Fish and Wildlife Service, Anadromous Fisheries Act administered by the National Marine Fisheries Service, Pacific Salmon Treaty administered by the National Marine Fisheries Service, and State of Oregon (General and Wildlife Funds). Citation: Jacobs S., J. Firman, G. Susac, D. Stewart and J. Weybright 2002. Status of Oregon coastal stocks of anadromous salmonids, 2000-2001 and 2001-2002; Monitoring Program Report Number OPSW-ODFW-2002-3, Oregon Department of Fish and Wildlife, Portland, Oregon. CONTENTS EXECUTIVE SUMMARY..................................................................................1 Fall Chinook ............................................................................................................................1 Coho ........................................................................................................................................2 Chum .......................................................................................................................................3
    [Show full text]
  • Federal Register/Vol. 75, No. 101/Wednesday, May 26, 2010
    Federal Register / Vol. 75, No. 101 / Wednesday, May 26, 2010 / Proposed Rules 29489 Since nothing in the rule requires regulations under the ESA and status can be found in our February 11, those persons who submit reports designating critical habitat for this ESU 2008, final rule (73 FR 7816), classifying pursuant to this rule to keep copies of will remain in effect. this ESU as a threatened species. any records or reports submitted to us, DATES: Information and comments on To summarize that history, on July 25, recordkeeping costs imposed would be this proposal must be received by July 1995 we first proposed to list the ESU zero hours and zero costs. 26, 2010. A public hearing will be held as threatened (60 FR 38011). We withdrew that proposal in response to Authority: 44 U.S.C. 3506; delegation of promptly if any person so requests by authority at 49 CFR 1.50. July 12, 2010. Notice of the location and the State of Oregon’s proposed conservation measures as described in Issued on: May 21, 2010. time of any such hearing will be published in the Federal Register not the Oregon Plan for Salmon and O. Kevin Vincent, less than 15 days before the hearing is Watersheds (62 FR 24588; May 6, 1997). Chief Counsel. held. On June 1, 1998, the U.S. District Court [FR Doc. 2010–12664 Filed 5–25–10; 8:45 am] for the District of Oregon found that our ADDRESSES: You may submit comments BILLING CODE 4910–59–P determination to not list the OC coho identified by 0648–XO28 by any of the salmon ESU was arbitrary and following methods: • Electronic Submissions: Federal e- capricious (Oregon Natural Resources DEPARTMENT OF COMMERCE Rulemaking Portal: http:// Council v.
    [Show full text]
  • West Fork Smith River Environmental Assessment
    U.S. Department of the Interior Bureau of Land Management DOI-BLM-ORWA-C030-2017-0001-EA West Fork Smith River Environmental Assessment February 15, 2019 OR/WA Bureau of Land Management Coos Bay District, Umpqua Field Office 1300 Airport Lane North Bend, OR 97459 (541) 756-0100 [email protected] i | West Fork Smith River Environmental Assessment | DOI-BLM-ORWA-C030-2017-0001-EA | February 15, 2019 CHAPTER 1 PURPOSE AND NEED ................................................................................................................ 1 INTRODUCTION .......................................................................................................................................................... 1 PROJECT AREA LOCATION ......................................................................................................................................... 1 ACRES CONSIDERED AND ELIMINATED FROM PROPOSED PROJECT ............................................................................ 1 NEED .......................................................................................................................................................................... 4 PURPOSE (OBJECTIVES) .............................................................................................................................................. 5 DECISIONS TO BE MADE ............................................................................................................................................. 5 CONFORMANCE WITH LAND USE PLAN .....................................................................................................................
    [Show full text]
  • APPENDIX a to the PACIFIC COAST SALMON FISHERY MANAGEMENT PLAN As Modified by Amendment 18 to the Pacific Coast Salmon Plan
    APPENDIX A TO THE PACIFIC COAST SALMON FISHERY MANAGEMENT PLAN As Modified by Amendment 18 to the Pacific Coast Salmon Plan IDENTIFICATION AND DESCRIPTION OF ESSENTIAL FISH HABITAT, ADVERSE IMPACTS, AND RECOMMENDED CONSERVATION MEASURES FOR SALMON Pacific Fishery Management Council 7700 NE Ambassador Place, Suite 101 Portland, OR 97221-1384 (503) 820-2280 http://www.pcouncil.org September 2014 ACKNOWLEDGMENTS The primary drafting of this document was accomplished by Dr. John Stadler, Kerry Griffin, and Eric Chavez. GIS mapping was contributed by Barbara Seekins and Charleen Gavette. Additional contributions were provided by (in alphabetical order) Scott Anderson, F. Dale Bambrick, Alice Berg, Stephanie Burchfield, Sean Callahan, Scott Carlon, Renee Coxen, Rebecca Dittmann, Brian Ellrott, Dr. Jeffrey Fisher, William Foster, Michael Grady, Mark Hampton, Dr. Peter Kiffney, Keith Kirkendall, Gayle Kreitman, Steven Landino, William Lind, Michael Lisitza, Jeffrey Lockwood, Matthew Longenbaugh, David Mabe, Robert Markel, Michael McDonald, Michelle McMullen, Ben Meyer, Kenneth Phippen, Dr. Phil Roni, Bonnie Shorin, Dr. Thomas Sibley, Jim Simondet, Dr. Brian Spence, Kenneth Troyer, Randy Tweten, Julie Weeder, and David White. Final compilation and editing were done by Kim Ambert and Chuck Tracy. Partial funding for this effort was secured by Michael Tehan, Assistant Regional Administrator for Habitat Conservation Division, Northwest Region, National Marine Fisheries Service. TABLE OF CONTENTS LIST OF ABBREVIATIONS, ACRONYMS, AND INITIALISMS ....................................................
    [Show full text]
  • An Abstract of the Thesis Of
    AN ABSTRACT OF THE THESIS OF Nancy Raskauskas for the degree of Honors Bachelors of Science in Fisheries Science presented on December 9, 2005 Title: Cool Hideaways: Use of Summer Temperature Refuges by Juvenile Coho Salmon in the West Fork Smith River Abstract approved: ________________________________________________________ Judith L. Li The West Fork Smith River, a 69 km2 watershed in the Coast Range of Oregon, is prone to short periods of very high water temperature in mid-summer due to a combination of human and natural influences. In the summers of 2003 and 2004 more than 400 juvenile coho salmon regularly packed themselves into a 4m2 area of cooler water near Crane Creek. In the same watershed, other groups of coho salmon and trout were monitored in three other cold refuges where they avoided main channel water temperatures that reached as high as 25oC. In 2003 we mapped cold refuges and performed snorkel surveys and fish counts at several sites. In 2004 we chose four main refuges as study sites. We installed temperature loggers in each refuge and nearby main channel. We measured (length, weight) and PIT- tagged juvenile coho salmon at each site in early July and recaptured and measured fish in September. We tracked fish movement throughout the summer using a portable PIT- tag reader and snorkel surveyed to count fish numbers in the refuges and nearby pools at various water temperatures and to observe fish behavior. However, of the 178 coho salmon tagged only 50 were recaptured. 1 Local fidelity to refuge sites, in association with peak temperatures in mid summer best describes juvenile coho use of coldwater refuges at West Fork Smith River.
    [Show full text]
  • Umpqua Basin Total Maximum Daily Load (TMDL
    CHAPTER 7 UMPQUA BASIN WATER QUALITY MANAGEMENT PLAN (WQMP) Prepared by: Oregon Department of Environmental Quality Submissions by: Oregon Department of Agriculture Oregon Department of Forest Oregon Department of Transportation USDA Forest Service and USDI BLM Partnership for the Umpqua Rivers Umpqua Basin TMDL: Water Quality Management Plan October 2006 Table of Contents PART I. INTRODUCTION.............................................................................................. 1 Douglas County........................................................................................................................................................2 Oregon Department of Agriculture........................................................................................................................2 Oregon Department of Forestry.............................................................................................................................2 USDI-Bureau of Land Management, USDA-Forest Service................................................................................2 Oregon Department of Transportation .................................................................................................................2 DEQ - NPDES Permitted Operations ....................................................................................................................3 The incorporated cities in Douglas County ...........................................................................................................3 B.
    [Show full text]
  • Umpqua Basin TMDL and WQMP Response to Public Comments
    Umpqua Basin Total Maximum Daily Loads (TMDLs) & Water Quality Management Plan (WQMP) Response to Public Comments Prepared by: Oregon Department of Environmental Quality October 2006 Umpqua Basin TMDL: Response to Comments October 2006 Introduction This Response to Public Comments document addresses comments received regarding the Draft Umpqua Basin Total Maximum Daily Load (TMDL) and Water Quality Management Plan (WQMP) dated February 2006. Grammatical, editorial, and formatting errors noted by reviewers are not addressed here but corrections have been made in the document where necessary. The Oregon Department of Environmental Quality (ODEQ) appreciates the time and effort that all the commenters put into reviewing the document. All comments have been considered by ODEQ and, where appropriate, have been addressed in the final document that has been submitted to the Environmental Protection Agency (EPA). EPA will then either approve or disapprove the TMDL. Background The public comment period on the proposed TMDL and WQMP opened February 21, 2006. Written and oral comments were received during the public comment period that extended through April 24, 2006. Four information sessions were provided around the basin prior to the formal public hearings in Reedsport (City Hall) March 30, 2006 and Roseburg (Courthouse Church Annex Building) April 6, 2006. One commenter provided ORAL comments at the public hearing in Reedsport. Remaining comments received by ODEQ were submitted in written (paper and electronic) form. The TMDL and WQMP were available for downloading from ODEQ’s website throughout the comment period. Hard copies and CDs of the document were also available for viewing at ODEQ’s offices in Roseburg and Portland.
    [Show full text]
  • LCM Annual Report 1998-1999
    for Salmon and Watersheds Salmonid Life-Cycle Monitoring Project, 1998 and 1999 REPORT NUMBER: OPSW-ODFW-2000-2 SALMONID LIFE-CYCLE MONITORING PROJECT 1998 AND 1999 Oregon Plan for Salmon and Watersheds Monitoring Report No. OPSW-ODFW-2000-2 March 2, 2000 Mario F. Solazzi Steven L. Johnson Bruce Miller Tim Dalton Coastal Salmonid Inventory Project Western Oregon Research and Monitoring Program Oregon Department of Fish and Wildlife 28655 Highway 34 Corvallis, OR 97333 Funds provided in part by: Oregon Department of Fish and Wildlife Sport Fish and Wildlife Restoration Program administered by the U.S. Fish and Wildlife Service Bureau of Land Management Salem and Coos Bay Districts Oregon Plan for Salmon and Watersheds Tillamook Bay National Estuary Program Oregon Department of Forestry Citation: Solazzi, M.F., S.L. Johnson, B. Miller, T. Dalton 2000. Salmonid Life-Cycle Monitoring Project 1998 and 1999. Monitoring Program Report Number OPSW-ODFW-2000-2, Oregon Department of Fish and Wildlife, Portland, Oregon. ii TABLE OF CONTENTS PART I. SMOLT AND ADULT MONITORING………………………………………………………..1 Introduction............................................................................................................................. 1 Description of Sub-basins ....................................................................................................... 1 North Fork Scappoose Creek (Lower Willamette)................................................................ 1 North Fork Nehalem River..................................................................................................
    [Show full text]
  • Monitoring the Effectiveness of Culverts Replaced Or Retrofitted for Fish Passage in the Upper West Fork of Smith River, Oregon
    Monitoring the Effectiveness of Culverts Replaced or Retrofitted for Fish Passage in the Upper West Fork of Smith River, Oregon Bruce P. Hansen Gordon H. Reeves Aquatic and Land Interactions Program, PNW Research Station Corvallis, OR SUMMARY history stage. Motivation for movement includes response to changing environmental conditions either seasonally All of the culverts in this study passed juvenile coho or from the alteration of existing conditions, and meeting salmon and cutthroat at a wide range of flows, suggesting reproductive needs and age or life-history stage specific that the current design criteria for these culverts were habitat requirements (Kahler and Quinn 1998; Hoffman adequate to ensure juvenile fish passage. There appear and Dunham 2007). Preserving connectivity among to be patterns in the timing, frequency, and magnitude habitats within a watershed is crucial to the persistence of of upstream and downstream pre-smolt movement. The species dependent on periodic movements (Young 1994; upstream movement of both juvenile coho salmon and Fausch et al. 2002). cutthroat trout in the West Fork of Smith River was triggered Barriers, anthropogenic or natural, can have important by the first fall freshets and tapered off through the rest of ecological effects on fish movement. They may limit access the year. Downstream movement was spread throughout to food resources, reproductive sites, and seasonal refugia the year. Virtually all of the upstream movement occured (Hilderbrand and Kershner 2000). They can also restrict during flows at or below the 2% exceedance level (i.e., 2% interactions among populations of a given species, which of the flows at the site are greater than this flow), with the may reduce the likelihood of persistence of some populations vast majority happening at or below the 10% exceedance.
    [Show full text]