Assessment of A-run Steelhead population in the Clearwater Nez Perce Tribe Department of Fisheries Resources Management.

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