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Using Genetic Tools to Manage Scottish Salmonid Fish Populations Lessons from Recent studies & Implications for Management
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Feb 18, 2018

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  • Using Genetic Tools to Manage Scottish Salmonid Fish Populations

    Lessons from Recent studies & Implications for Management

  • The big leap forwardThe big leap forward

    Loch Feochan StudyLoch Feochan StudyImplications for Implications for

    management;management;Genetic AuditsGenetic AuditsAssociated Life historyAssociated Life historyExploitationExploitationHabitat & Water Habitat & Water Resource ManagementResource ManagementRestoration & Farm Restoration & Farm escapes escapes

  • Feochan Study Feochan Study Determine stock composition of net Determine stock composition of net fishery fishery Investigate sustainability of the Investigate sustainability of the fisheryfisheryInvestigate stock structures in Nell Investigate stock structures in Nell & Euchar Rivers& Euchar RiversInvestigate stock abundance?Investigate stock abundance?Provide insight into potential of Provide insight into potential of genetic basis for managementgenetic basis for managementProvide Management Advice to Provide Management Advice to local fisherieslocal fisheries

    Investigate potential for farm fish Investigate potential for farm fish interbreedinginterbreedingProject partners; AFT, FRS & ASTProject partners; AFT, FRS & AST

  • Sampling Sampling 20052005--0606....

    Lower EucharN = 48 Upper Euchar

    N = 47

    Mid EucharN = 71

    LonanN = 48

    Feochan BheagN = 46

    Dunach fishery2005 N = 762006 N = 25

    NellN = 50

    Lower EucharN = 48 Upper Euchar

    N = 47

    Mid EucharN = 71

    LonanN = 48

    Feochan BheagN = 46

    Dunach fishery2005 N = 762006 N = 25

    NellN = 50

    AFT electrofishing and net sampling

    FRS Genetic analysis & interpretation

    AST - funding

  • Genetic distance measures of absolute levels of differentiation.

    3.56

    2.17

    2.021.92

    1.21

    2.62

    1.82

    0.33

    1.301.670.70

    1.82

    2.02

    1.30

    1.23 3.56

    2.17

    2.021.92

    1.21

    2.62

    1.82

    0.33

    1.301.670.70

    1.82

    2.02

    1.30

    1.23

  • General FindingsGeneral Findings1. Genetic structuring of juveniles - Significant

    differences between & within catchments 2. Mechanism - Topographical features; Lochs,

    waterfalls & tributaries3. Fishery Exploitation Fishery is exploiting ALL

    parts of both catchments, upstream sites may be more vulnerable.

    4. Net catch exploitation Both Rivers, catch of 100 fish represents 17 to 30% of breeding individuals.

    5. Effective population size estimates of 338-583 salmon in Loch Feochan systems.

    6. Detecting farmed escapes Lack of baseline data on farm populations

  • Implications for managementImplications for managementA New level of A New level of

    consciousnessconsciousnessInform & focus;Inform & focus;-- Management plansManagement plans-- ExploitationExploitation-- Restoration initiativesRestoration initiatives-- Habitat managementHabitat management-- Conserve diversityConserve diversity-- Enhancement stockingEnhancement stocking-- Target resources Target resources

  • Genetic AuditGenetic Audit

    6060--100 catchments with 100 catchments with migratory salmonids in Argyllmigratory salmonids in Argyll

    PrioritisePrioritise on the basis of ?;on the basis of ?;

    Potential diversityPotential diversityFishery valueFishery valueExisting pressuresExisting pressuresAvailable resourcesAvailable resources

  • Associated life historyAssociated life historyInvestigate Investigate

    characteristics of characteristics of breeding groups;breeding groups;Age at smoltAge at smoltSea ageSea ageAdult return timingAdult return timingMorphologyMorphologyEnvironmental factorsEnvironmental factorsMissing groupsMissing groups

  • Control of exploitationControl of exploitationIdentify strong & Identify strong & weak componentsweak componentsControl Control exploitation in exploitation in relation to run relation to run timingtimingSet conservation Set conservation limitslimitsRaise awareness Raise awareness amongst fishersamongst fishers

    0

    2000

    4000

    6000

    8000

    10000

    12000

    14000

    1952

    1956

    1960

    1964

    1968

    1972

    1976

    1980

    1984

    1988

    1992

    1996

    2000

    2004

    Year

    No.

    Salm

    on &

    Gril

    se

    ArranIslayMullSouth ArgyllLoch FyneKintyreLower LornLinnhe

  • Focus Habitat managementFocus Habitat managementUnderstand influence of catchment

    characteristicsDegradationReduction Fragmentation

    Prevent declinewater resourcesLand use

    Better use of available resources

  • Restoration ActivitiesRestoration Activities

    Inform hatchery intervention Inform hatchery intervention strategies;strategies;Broodfish selectionBroodfish selectionHatchery infrastructureHatchery infrastructureStocking locationsStocking locationsReplicate wild scenarioReplicate wild scenario

    Conservation focus;Conservation focus;Support vulnerable Support vulnerable populationspopulationsAvoid inbreeding Avoid inbreeding depressiondepressionReRe--introduce lost introduce lost componentscomponents

  • Farm escapes & stockingFarm escapes & stocking

    Impacts largely unknown in Scottish contextEcological & genetic Reduction of performance Long term consequences?

    Detecting influenceBase-line informationA political will to focus on this issue

  • SummarySummaryDemonstration of stock structuring & abundanceImprove & Focus Management of fisheries & habitatsUnderpin management plans & activitiesAvoid further Loss of biodiversity & stock performance from;

    over-exploitationHabitat degradationInappropriate stockingInteractions with farm fish