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Catastrophes and Recovery Goals. The Question: . What is the number and distribution of populations needed for a sustainable ESU?. Spatial Scale. Population (as per VSP) reproductive isolation independent demographics and intrinsic extinction risk ESUs may contain multiple populations.

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Presentation Transcript
the question
The Question:
  • What is the number and distribution of populations needed for a sustainable ESU?
spatial scale
Spatial Scale
  • Population (as per VSP)
    • reproductive isolation
    • independent demographics and intrinsic extinction risk
  • ESUs may contain multiple populations
the laundry list of catastrophes
The laundry list of catastrophes
  • Weather (draughts, floods)
  • Oil Spills / Shipping Risks
  • Landslides / Mass Wasting
  • Epidemics
  • Dam/Water Diversion Failure
  • Major mistakes in harvest
  • Chemical contamination
  • Volcanoes
  • Earthquakes
  • Fires
major challenges
Major Challenges
  • Predict the frequency, spatial extent and severity of potential catastrophic events
  • Establish the link between the event and salmon survival or behavior
  • Translate impacts on salmon into population and ESU level extinction risk
example southern sea otter
Example: Southern Sea Otter
  • Ralls et al. 1996
  • Oil Spill considered most serious threat
  • Extensive modeling potential of oil spill
  • Related spill probabilities to number of contacted otters
  • Estimated mortality per contact from Exxon Valdez data
slide7

Simulated

California

Oil Spills

major oil spills in washington
Major Oil Spills in Washington

Spills >10,000 gallons over 14 year period.

(State of Washington Dept. of Ecology)

simsalmon
SimSalmon

Nx = Number at time x

Rx = Spawners produced per Spawner at time x

R is a stochastic variable with a lognormally

distribution that can be estimated from data

Ai = Fraction that mature at age i

more bits on simsalmon
More Bits on SimSalmon…
  • Extinction:
    • If Nt < Depensataion Threshold, Rt =0
    • The population is extinct if N = 0 for a number of years in a row equal to the maximum age at maturation.
  • Density Dependence
    • Simple Ceiling
    • If Nt > K, then Nt = K
sample data set
Sample Data Set

Snake River Fall Chinook

(PATH 1999)

question for simsalmon
Question For SimSalmon
  • What is the affect of losing an entire year class on extinction risk?
simulation conditions
Simulation Conditions
  • Distribution of R
    • Lognormal, mean = 1, variance = 1.72
  • Depensation threshold = 10
  • Age distribution
major challenges26
Major Challenges
  • Predict the frequency, spatial extent and severity of potential catastrophic events
  • Establish the link between the event and salmon survival or behavior
  • Translate impacts on salmon into population and ESU level extinction risk
esu viability guidelines
ESU Viability Guidelines
  • ESUs should contain multiple populations.
  • Populations in an ESU should be geographically widespread.
  • Populations should be geographically close to each other.
  • Populations should not all share common catastrophic risks.
  • Populations that display diverse life-histories and phenotypes should be maintained.
  • Some populations should exceed VSP guidelines.
  • Evaluations of ESU status should take into account uncertainty about ESU-level processes.
final thoughts
Final Thoughts
  • Catastrophes can be the largest risk.
  • Catastrophic risk will not be eliminated and needs to be incorporated into large scale recovery plans.
  • Collaboration across many disciplines will be required.
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