Report on Okanagan Lake Status of Fish Stocks and - PowerPoint

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					       Report on Okanagan Lake
Status of Fish Stocks and Recovery Strategies
                           By
                     Steve Matthews
               Senior Fisheries Biologist
  Ministry of Water, Land and Air Protection, Penticton
            Presentation Outline
• Okanagan Lake Background Information

• Impacts to Fish Populations

• Kokanee Stock Status Summary

• Okanagan Lake Kokanee Recovery Plan Progress
  Report

• Future Directions
Site Description
                   Fish Species
• 18 species of fish
• Indigenous species
  include rainbow trout
  and kokanee
• Large number of
  introduced species
Major Impacts on Okanagan
Lake Kokanee Populations

• Habitat Loss

• Low In-lake Survival
               Habitat Loss




• 90% of salmonid stream habitat lost due to
  land development activites including
  agriculture, logging and urbanization
        Low In-Lake Survival
• Lake level fluctuations
• Competition with
  Mysis relicta
• Nitrogen:Phosphorus
  Imbalance
                                                       Okanagan Lake Blue-green abundance & biomass


                                                2000
                                                1800                  Nov-02
                            cells/mL & mm3/mL   1600
                                                1400                  Feb-03

                                                1200
                                                1000
                                                 800
                                                 600
                                                 400
                                                 200
                                                   0
                                                        OK1    OK3     OK4     OK6   OK7   OK8
                         Kokanee
• Severely depressed
  population

• Keystone species
  - indicator of health of
    ecosystem

• Many species reliant on
  kokanee as prey
Recent review by Cederholm et al. (2000)
identified 137 species of birds, mammals,
amphibians and reptiles as predators/scavengers
of salmonids
                       Okanagan Lake Kokanee Shore and
                          Stream Spawner Estimates


                     1000

                      900

                      800

                      700
# Spawners (x1000)




                      600
                                                                                     Major Stream Totals
                      500
                                                                                     Shore Totals
                      400

                      300

                      200

                      100

                        0
                            71   73   75   77   79   81   83   85     87   89   91   93   95   97   99   2001

                                                                    Year
 Estimates of Okanagan Lake Kokanee
Population from Hydroacoustic Surveys


                     16
                     14
 Number of Kokanee




                     12
    (in millions)




                     10
                     8
                     6
                     4
                     2
                     0
                          88   89   90   91   92   93   94   95   96   97   98   99   00   01   02
                                                        Survey year
        Kokanee Recovery Strategies
• All activities directed by the
  Okanagan Lake Action Plan
   – developed in 1995

   – Comprehensive 20 year plan

   – Considerable stakeholder input

   – Currently delivering Year 8 of
     10 year HCTF funding
     commitment

   – 5 primary areas of focus
    Habitat Protection / Restoration
• Regulatory controls on
  development

• Flows for fish

• Stream restoration
              Mysis relicta Removal
          Commercial Fishery Feasibility Studies
•   Harvesting experiments
•   Market analysis
•   Bycatch investigations
•   Test Fishery
•   Modeling
         Nutrient Investigations

• Assessing feasibility
  of nitrogen enrichment

• Adaptive management
  approach
   – small incremental steps
   – reversible impacts


• Extensive consultative
  process
            Improved Lake Level
               Management
• Working at
  maximizing fish
  production within
  flood control and
  social constraints

• Providing better tools
  to water managers
              Long Term Monitoring
• Limnology
   –   physical conditions
   –   water chemistry
   –   phyto/zooplankton
   –   mysis


• Kokanee stock status
   – in-lake population
     estimates
   – spawner enumerations
   – length/age information
   – genetics
      Okanagan Lake Action Plan
       Future Direction - Primary Focus

• Long term monitoring
• Habitat protection / restoration
• Mysis relicta large-scale removal
• Improved lake level management
• N:P ratio adjustment feasibility
  investigations
• Recreational fishery management
  plan
• Communications