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Matt Maples Fisheries Biologist Nevada Department of Wildlife – Western Region

Lower Truckee River Bioassessment Symposium January 5 & 6, 2009 Desert Research Institute Status Report on Fish Populations in the Truckee River. Matt Maples Fisheries Biologist Nevada Department of Wildlife – Western Region. Outline. Historical perspective Present day fish population

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Matt Maples Fisheries Biologist Nevada Department of Wildlife – Western Region

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  1. Lower Truckee River Bioassessment SymposiumJanuary 5 & 6, 2009Desert Research InstituteStatus Report on Fish Populations in the Truckee River Matt Maples Fisheries Biologist Nevada Department of Wildlife – Western Region

  2. Outline • Historical perspective • Present day fish population • Stocking program • Description of river zones • 2008 survey results • Management objectives and strategies

  3. HistoricalPerspective Truckee River supported tremendous spawning runs of native Lahontan cutthroat trout (LCT) that lived in Pyramid Lake and Lake Tahoe. Photo courtesy of Buck Wheeler

  4. Historical Perspective The LCT fishery dwindled in the early 1900s and eventually the original Pyramid Lake strain was lost around 1940 due to water diversions, passage barriers, over-harvest, habitat alteration, increased human development and non-native species.

  5. Present Day Fishery: Salmonids • Non-native rainbow and brown trout now dominate the salmonid population in the Truckee River and provide a significant recreational fishery. • LCT presence in the Truckee River is maintained by an annual stocking program. • Mountain whitefish (native) are typically found in moderate to high densities upstream of Vista Blvd.

  6. Present Day Fishery: Salmonids

  7. Present Day Fishery:Native, Non-Salmonids Native, non-salmonid species persist in the Truckee River and their individual contribution to the fishery varies by reach and habitat type.

  8. Present Day Fishery:Non-Native, Non-Salmonid • Many non-native, non-salmonids have been inadvertently introduced into the Truckee River, their impact on the fishery appears to be minimal, but we have little data to confirm this hypothesis. • Species include: • Green sunfish • Largemouth bass • Fathead minnow • Mosquito fish • Common carp http://www.uaex.edu/wneal/pond_management/images/greensunfish.jpg

  9. Present Day Fishery:Species Composition

  10. Stocking Program Trout are stocked between March and October – dependent on flows and water temperature. LCT are stocked throughout the Nevada portion of the Truckee River. All rainbow trout are triploid and are only stocked upstream of the East McCarran Bridge.

  11. Stocking Program: History LCT have been stocked in the Truckee River for many years. Most recent “peak” in stocking numbers reflects renewed interest in LCT Recovery and the MOA with PLPT.

  12. River Zones • For management purposes, the Truckee River is divided into eight zones, which span from Pyramid Lake to Tahoe Dam. • Four of these zones are actively managed by the Nevada Department of Wildlife.

  13. Zone Divisions Zone 2: Wadsworth to Derby Dam Zone 3: Derby Dam to E. McCarran Bridge Zone 4: E McCarran to Mayberry Bridge Zone 5: Mayberry Bridge to State Line

  14. Fall 2008 – Electrofishing Survey NDOW completed nine transects along the Truckee River, from Painted Rock to Verdi Power Dam.

  15. Fall 2008 – Electrofishing Survey We use a tote-barge that is equipped with a generator powered electrofishing unit.

  16. Fall 2008 – Electrofishing Survey All fish were counted, measured, weighed and released back into the river.

  17. Zone 2

  18. Zone 2 Results: Brown trout N = 6 16.7 fish/mile

  19. Zone 2 Results: Rainbow trout N = 65 152 fish/mile

  20. Zone 2 Results: Species Diversity 333 Fish Captured 10 Species 3 Undesirables

  21. Zone 3

  22. Zone 3 Results: Brown trout N = 1 6 fish/mile

  23. Zone 3 Results: Rainbow trout N = 9 50 fish/mile

  24. Zone 3 Results: Species Diversity 120 Fish Captured 4 Species 0 Undesirables

  25. Zone 4

  26. Zone 4 Results: Brown trout N = 157 312 fish/mile

  27. Zone 4 Results: Rainbow trout N = 148 333 fish/mile

  28. Zone 4 Results: Species Diversity 966 Fish Captured 9 Species 1 Undesirable

  29. Zone 5

  30. Zone 5 Results: Brown trout N = 120 354 fish/mile

  31. Zone 5 Results: Rainbow trout N = 119 315 fish/mile

  32. Zone 5 Results: Species Diversity 653 Fish Captured 8 Species 0 Undesirables

  33. Mountain Whitefish Typically present in good densities upstream of Rock Park. In 2008, we documented whitefish below Derby Dam in the Spring and Fall. Result of increased downstream flows and adequate summer temperatures. Photo Credit: Doug Ouellette

  34. Mountain Whitefish N = 360 408 fish/mile

  35. Wild Trout Populations Young rainbow and brown trout were found in low densities at Zone 2 and 3, but were found in moderate to high densities in Zone 4 and 5. Photo Credit: Doug Ouellette

  36. Wild Rainbow Trout

  37. Fishery Restoration: Lahontan cutthroat trout In October 2002, NDOW and the Pyramid Lake Paiute Tribe signed a MOA and agreed to work toward restoration of LCT in the Truckee River. Objectives: • Reestablish a natural run of LCT up the Truckee River • Utilize LCT to maintain the recreational fishery in the Truckee River

  38. Fishery Restoration:Lahontan cutthroat trout Strategies • De-emphasize stocking non-native salmonids where feasible • Utilize triploid rainbows in high angler-use areas • Stock LCT fry in the upper reaches and tributaries of the river • Ongoing monitoring to assess effectiveness of various management strategies

  39. Fishery Restoration:Lahontan cutthroat trout Ongoing Activities • Pursue opportunities to utilize streamside incubators in the upper river (Verdi area). • Continue to encourage habitat improvement and restoration of the lower Truckee River. • Continue to work with USCOE and support the assessment and removal of fish passage barriers on the Truckee River.

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