The Effects of Seasonal Stream Dewatering on Bull Trout, Salvelinus confluentus Thesis Presentation and Defense By William R. Meyer Central Washington University
Introduction Bull trout life history The importance of dewatering The research objectives Study sites Methods Results Historical conditions Conclusions
Bull Trout Life History Earliest accounts of the genus are from 1896 (Jordan and Evermann). Status: Federally Threatened Habitat: Cold (<15 o C) clean water in mountainous regions. Food: Juveniles Aquatic insects Adults - Fish The four Life History Patterns: Fluvial (Rivers) Resident (Small Streams) Anadromous (River/Sea) Adfluvial (Lakes and Reservoirs) Photo by: Ernest Keeley
Distribution of bull trout in Washington State Yakima River Basin
Yakima River Basin Lake Keechelus Lake Kachess Ellensburg Yakima River
The relevance of dewatering events Occurs frequently in many headwater bull trout streams. Can cause high adult mortality. Stranding of fry and juveniles.
Stream Dewatering at Gold Creek July 20, 2000
August 1, 2000 August 15, 2000
The Research Objectives Examine the effects of stream dewatering on bull trout density, movement, and survival. Determine the influence of reservoir management on stream dewatering. Investigate the natural and historical land management influences on dewatering.
Hypotheses I. Juvenile densities should increase as stream discharge decreases. II. The timing of adult migration and spawning will be constrained in systems that dewater.
Study Sites Gold Creek Kachess River (Box Canyon Creek) N Interstate 90
Kachess River Waterfalls
Gold Creek
Methods Night Snorkeling for Juveniles Densities every two weeks Day Snorkeling for Adults Presence, before and after dewatering Redd Surveys Stream temperature and discharge Historical Information The Kachess River report (Parsons 1980) Aerial and ground photos (USFS) Survey Data (WDFW, USFS, USFWS, CWU)
Night Snorkeling
Juvenile Measurements
Results Juvenile densities and numbers Timing of adult migration and spawning Reservoir effects on dewatering Historical land management influences on dewatering
Juvenile Densities at Kachess River Density (#/100m) Density (#/100m 2 ) 7 6 BT CT/RB 5 4 3 2 1 0 7/25 8/22 9/6 9/20 Date 10/4 5 4 CT/RBT BT 3 2 1 0 7/25 8/9 8/22 9/6 9/20 10/4 10/18 11/3 11/16 Date
What causes the decline? Movement? Mortality? - Temperature - Piscivory - Electrofishing Sampling Error
Temperature (ºC) Stream temperature at Kachess River 20-Jul 26-Jul 1-Aug 7-Aug 13-Aug 19-Aug 25-Aug 31-Aug 6-Sep 12-Sep 18-Sep 24-Sep 30-Sep 6-Oct 12-Oct 18-Oct 24-Oct 30-Oct 5-Nov 11-Nov 16 14 12 10 8 6 4 2 0 Date
Density (#/100m 2 ) Density (#/100m 2 ) Juvenile densities at Gold Creek 1.6 1.2 CT/RBT Bulltrout Brook 0.8 0.4 0 7/19 8/1 8/15 8/30 9/13 9/27 10/12 10/26 11/9 Date 1.6 1.2 CT/RBT Bulltrout Brook 0.8 0.4 0.0 7/19 8/1 8/15 8/30 9/13 9/27 10/12 10/26 11/9 Date
18-Jul 25-Jul 1-Aug 8-Aug 15-Aug 22-Aug 29-Aug 5-Sep 12-Sep 19-Sep 26-Sep 3-Oct 10-Oct 17-Oct 24-Oct 31-Oct 7-Nov Stream Discharge (cfs) Stream discharge at Kachess River 50 40 30 20 10 0 Date
Results Juvenile densities and numbers Timing of adult migration and spawning Reservoir effects on dewatering Historical land management influences on dewatering
The Mystery of Kachess River Bull trout juveniles present, but no spawning observed for over 20 years. Resident or Adfluvial?
Past Surveys for Adult Bull Trout Kachess River Date Observer Stream Condition Adults? 5/6/9 1980 Brown WDFW Flowing/Dewatered No Oct. 7, 1980 Brown WDFW Flowing 4 Adults Oct. 13, 1984 Kessler USFWS Dewatered 4 Adults Aug/Oct 1993 Brown WDFW Dewatered No June 1996 Mongillo WDFW Flowing No Sept. 1996 Larrick USBR Dewatered No Oct. 1996 Craig USFWS Dewatered No July 1998 Craig USFWS Flowing No Sept. 1998 Anderson WDFW Dewatered No Oct/Nov 2000 Meyer/Anderson Flowing 6 Adults Sept. 2001 Meyer CWU Dewatered No Oct. 2001 Anderson WDFW Flowing Adults
Timing of Migration and Spawning in 2000 La ke K a c h e s s K a c h e s s R iv e r La ke K a c h e s s B o x C a n y o n C re e k La ke K e e c h e lu s B u mp in g La ke Go ld C re e k D e e p C re e k R imro c k La ke R imro c k La ke S o u th F o rk T ie to n R iv e r In d ia n C re e k Ja n F e b M a r A p r M a y Ju n Ju l A u g S e p O c t N o v D e c
1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 Number of Redds Historic Redd Counts (WDFW Data) 60 50 40 30 20 10 0 Year Box Canyon Kachess River Gold Creek
Adult Bull Trout mortality due to dewatering 10% mortality of the spawning population (~30) at Kachess River in 2000. 63% mortality of the spawning population (~25) at Gold Creek in 1993 (Wismar &Craig).
Results Juvenile densities and numbers Timing of adult migration and spawning Reservoir effects on dewatering Historical land management influences on dewatering
Elevation (ft) Reservoir Levels and Dewatering 2530 Reservoir Elevations 2510 2490 2470 2450 Kachess Keechelus 2430 1-Jun 1-Jul 1-Aug 1-Sep 1-O ct 1-Nov Date
Results Juvenile densities and numbers Timing of adult migration and spawning Reservoir effects on dewatering Historical land management influences on dewatering
Historical Conditions A view to the past: The USFS Kachess River Study - 1980 Past Resource Extraction and Management Mining: Copper Mine ~1900 at Mineral Creek Gold Mining ~1890-1900 s at Gold Creek Past Mining Logging: USFS and Plum Creek Timber Co. 1968-1986 Road Building: USFS 1960 s I-90 1970 s Kachess River at Present
How logging effects bull trout habitat and stream dewatering Habitat is Degraded by: - Increased stream velocities - Decreased woody material - Decreased sinuosity Dewatering worsened by: - Decreased channel stability - Increased alluvial deposition Logging through the Kachess River channel
1942
1975
1986 1 mile
1999
Effects of Roads Increased runoff Increased sediment deposition Increased stream temperatures Kachess River 1980
Past and Present at Kachess River 1980 2001 1980 1980 2001
Conclusions Juvenile densities shift throughout a season. Adult migration at Kachess River appears to have become locally adapted to dewatering. Reservoir drawdown has no direct effect on stream dewatering. The long term persistence of bull trout at Kachess River and Gold Creek is likely to depend upon habitat restoration.
Acknowledgements The committee: Paul James, David Darda, Patrick Bryan Field Assistance: Yuki Reiss One mean snorkeler, Cory Straub, MarkTuttle, Heather Simmons, Sallie Herman, Gary Lenhart, Brenda James, Charity Hervosma, and Patrick Bryan. Agency Support: Eric Anderson WDFW, Scott Kline USBR, Shan Madden USFS, Judy De La Vergne and Aaron Bosworth USFWS, Larry Brown WDFW.
The End
Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sept. Oct. Nov. Dec. Precipitation (cm) Precipitation at Kachess River in 2000 12 10 8 6 4 2 0 Date (Compared to a 30 yr average with a 95% C.I.)
Species Composition Cutthroat 41% Kachess River Brook Trout 2% Red sided shiner 1% Bull Trout 56% Bull Trout 8% Brook Trout 16% Gold Creek Mountain Burbot Whitefish 2% 6% Other 2% Cutthroat & Rainbow 66%
Number of Fish Number of Fish Juvenile Numbers at Kachess River 14 12 10 8 6 4 2 0 7/25 8/22 9/6 9/20 Date 30 25 20 15 10 5 0 7/25 8/9 8/22 9/6 9/20 10/4 10/18 11/3 11/16 Date Upper 600m Lower 400m
Effects of Historic Mining Blewett Pass Dredge mining operation ~ 1914 Kachess River at Present