Some considerations on the use of hatcheries for management of Atlantic salmon

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Some considerations on the use of hatcheries for
management of Atlantic salmon
P.McGinnity N. Ó Maoileidigh Oloron-Sainte-Ma
rie October 2009
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Each river has one or more genetically unique
salmon populations
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(No Transcript)
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Global population structure
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Structuration génétique des populations en 5
groupes
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Within river population structureDillane et al.
(2008) Molecular Ecology
Introduction
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Some of differences are historical
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LGM 20,000 yr BP
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So what? Adaptation
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Theoretical genetic models

• Natural selection in the wild in response to
  environmental variability, imposes demographic
  costs (Burger and Lynch, 1995 Evolution)
  CLIMATE
• Populations that are well adapted to their local
  environments increase toward the carrying
  capacity, while those whose trait values lie far
  from the local ecological optimum decline
  (Kirkpatrick and Barton, 1997 Evolution)
  STOCKING/ESCAPES

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Population response to changing environment or
mal-adapted genotypes
Gomulkiewicz Holt 1995 Evolution
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Is there any evidence to support idea of loss of
productivity?
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Reduction in productivity - Steelhead S/R studies
(Chilcote, 2003)
Productivity
Proportion of wild fish
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Empirical Evidence Common garden experiments -
Burrishoole
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Common Garden Experiments (Norwegian Farm v
Ireland wild)
McGinnity et al., 2003 Proc. R. Soc. B
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Fitness variation between neighbouring
populations (scale of local adaptation)
50Km
McGinnity et al., 2004 J. Fish Biol
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Domestication
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Sampling Error

• Small founder populations
• Ryman Laikre effect
• Broodstock mining
• Random breeding
• Accidents/disease

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Domestication selection
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Genetic signatures of domestication

• Transcription Profiles
• Roberge et al. 2006, Mol. Ecol. Study of
  transcription profiles of 3557 genes in the
  progeny of farmed and wild salmon from Norway and
  Canada grown in control conditions
• Norway farm Canada farm ? Canada wild

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Speed of change - Genetic Effects of Captive
Breeding Cause a Rapid, Cumulative Fitness
Decline in the Wild. Araki et al. 2007. Science
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Examples of adaptive differences (some insight
into the why?)
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Why differences? Example Interaction of climate
captive bred fish
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Long-term monitoring (Burrishoole River total
counts 1969-2009)
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The Model

• Main factors determining egg to smolt survival in
  Burrishoole
• hatchery eggs in spawning cohort (- survival)
• Winter temperature for eggs fry (- survival)
• Winter temperature for parr (- survival)
• Winter temperature for smolts ( survival)
• Interaction between hatchery eggs and winter
  temperature (- survival)

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Bioenergetics framework (suggested mechanism)
Little brown bat (Myotis lucifugus)

• Egg size
• Timing of spawning
• Timing of emergence
• Onset winter torper in parr (hibernation)

Humphries et al. 2002 Nature
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McGinnity et al. (2009) Proc. R. Soc. B
Projected climates 100 years
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Conclusions

• In context of providing natural self sustaining
  population
• Evidence that hatchery fish contributing to
  problem rather than providing the solution
• Fish adapt quickly to hatchery conditions
• Great care must be taken in making the decision
  to use a hatchery
• Must know status of wild population
• Need to resolve habitat, fisheries, access issues
  first
• Do not under-estimate capacity of wild
  populations to colonise-recolonise healthy rivers
• If hatchery fish used genetically type parental
  fish