assessment of a-run steelhead population in the clearwater nez perce tribe department of fisheries...
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Assessment of A-run Steelhead population in the Clearwater
Nez Perce Tribe
Department of Fisheries Resources Management
Snake River Steelhead ESU
• Listed as threatened
• Number of sub-populations– Snake River Subbasin– Clearwater River Subbasin
Clearwater Subbasin Steelhead
• Two populations (A-run and B-run)– Size, return-timing– Location of spawning
Adult Escapement to LGD
0
5
10
15
20
25
Year
A-r
un e
scap
emen
t (x1
0,00
0)
NMFS 2000
Estimated juvenile carrying capacity
0102030405060708090
100
85 87 89 91 93 95 97
Year
Per
cent
of C
arry
ing
Cap
acit
y
(NMFS 2000)
Declines A-run Steelheadin Clearwater
• Construction and Operation of Hydropower
• Environmental Factor– Natural variation– Man Induced (303d listings)
• Current Hatchery Practices ??– Loss of genetic diversity and spatial structure
(Milner and Teel 1985)
A-run Clearwater Steelhead Unknowns
• Current Status– Abundance– Productivity– Spatial Structure– Diversity
2000 BiopESU Populations
• … to be identified and defined using biological criteria and for the evaluation of ESU population status (viability) in accordance with NMFS’ viable salmon population approach (McElhany et al. 2000)
• … the need to assess population status to establish recovery goals and gauge change towards the goals (Action 179)
Proposed Study ObjectivesA-run Clearwater Steelhead Population
1. Abundance and productivity
2. Spatial structure and genetic diversity
3. Environmental effects
4. Communication results
1. Abundance and production
1. Spawner escapement • Adult Weir
2. Smolt yield /survival• Screw Trap
3. Juvenile densities • Snorkeling
1. Spawner escapement -- Adult Weir 2. Smolt yield / survival -- Screw trap3.Juvenile production/ densities -- Snorkeling
2. Spatial structure and genetic diversity
• Task 1. Genetic survey of population
- 30 populations (primarily lower basin)
- 10 genetic microsatellite markers
- Previous work mid-80’s, 90’s and 00’s
- Detect changes- Results used to develop plan to assess
cause
Task 2. Straying rates
• Radio tag A-run steelhead adults at LGD – PIT tagged juveniles and non marked fish
• Track to spawning grounds• Results
– Escapement to Clearwater and Snake Subbasins– Escapement to Big Canyon Creek– Prespawning mortality– Understanding of straying
3. Environmental Influence
• Big Canyon Creek (Tier 2)– Temperature– Instream Flow– Habitat
• Potlatch, Lapwai, Jacks, Bedrock, Cottonwood Creeks (Tier 1)– Temperature– Instream Flow
4. Communicate results
• Assessing and tracking recovery efforts– RPAs (NMFS 2000)– Regional Management and Harvest Actions
(Subbasin Summary 2001)
• Fully assess and understand the status or viability of the Snake River Steelhead ESU