Phaedra Budy

1
Bull trout population assessment and life history
characteristics in association with habitat
quality and land use a template for recovery
planning

• Phaedra Budy
• Utah Cooperative Fish Wildlife Research Unit
• Howard Schaller
• Jeff Kershner

2
Overall Project Goals

• Population abundance, density, and growth
• Juvenile (sub-adult)
• Adults
• Life-stage specific survival rates
• Movement
• Annual rates of population change
• Relationships between populations and survival
  versus habitat quality and land use
• Develop analytical tools for USFWS recovery
  planning and prioritize areas for habitat
  improvement

3
Imnaha Subbasin

• Proposed Sites
• Imnaha mainstem
• Lick Creek
• Big Sheep Creek
• Sites were chosen
• based on
• Need for basic population data for recovery
  planning
• Contrast in habitat quality
• At least some present or historical data
  available
• Subbasin contrast
• (Imnaha vs. Little Salmon)

4
Bull trout in the Imnaha

• Migratory and resident forms
• Population size unknown
• Some data
• Intermittent redd counts (USFS)
• Presence/absence surveys
• Isolated and limited
• trapping and
• snorkel surveys
• Radiotelemetry

5
Study Design

• Comprehensive population assessment
• Marking PIT and floy tags
• Recapture electroshocking, seining, screw
  traps, snorkeling (resighting), and trapping
• Weirs
• Screw traps at confluences
• Pass-through PIT tag antennae

Big

Sheep

Creek

Little

Sheep


Creek

North
Lick
Fork


Creek
Snake

River

Imnaha
South
River

Fork

6
Study Design

• Comprehensive population assessment (cont.)
• Snorkel surveys juvenile and adult abundance
  and density estimate
• Adult spawner and/or redd counts
• Fecundity, sex ratio, and age
• -- borrow from literature,
• sample scales for age

7
Study Design

• Stream and riparian habitat assessment (USFS)

Land use and current management (e.g., road
density or culvert failure rate) Riparian /
floodplain and habitat (e.g., fragmentation of
riparian vegetation) In channel and community
integrity (e.g., water temperature, sediment)
8
Expected Results

• Population abundance form M/R (/-) and snorkel
• Resident adults
• Migratory adults (trapping and redd counts)
• Juveniles
• Life-stage specific survival rates
• (e.g., egg-to-parr survival)
• Movement among streams and
• subpopulations
• Habitat use and preference
• (broad scale and micro-habitat)

9
Expected Results (cont.)

• Annual rates of Population Change (lambda)
• Pradel M/R model
• Lambda f apparent (recruitment survival)
• Simple life-cycle model
• predict annual rates of population change
  (lambda)
• to monitor trends
• response variable

10
Expected Results (cont.)

• Relationships between habitat quality and land
  use bull trout survival
• and abundance
• Broad Scale USFS sites as
• index of bull trout habitat,
• prioritizing streams etc
• Local habitat preference
• and limiting factors

11
Evaluate feasibility of pass-through PIT-tag
technology

• Larger PIT tags (23 mm)
• Cost Effective Passive hoop detection
• Backpack-wand mobile
• detection
• Feasibility check --2002 in smaller streams , 2-3
  sites per stream, near headwaters and at
  confluences
• Provides
• Recaptures
• Movement
• Microhabitat use

12
Needs and Limiting Factors

• For bull trout management and recovery planning
• Basic population abundance data
• Evaluate population status
• Monitor population trends and effectiveness of
  management actions
• Information about the relationship between
  habitat quality and population abundance
• Understand how habitat affects bull trout
  survival and movement
• Identify and prioritize core areas for habitat
  improvement
• Analytical tools and information on population
  attributes for bull trout planning
• other areas where data are lacking
• Cost effective methods for monitoring and
  evaluation