WWW PICES
Report 41 (August 2012)

PICES Advisory Report on the Decline of Fraser River Sockeye Salmon Oncorhynchus nerka (Steller, 1743) in Relation to Marine Ecology

   
  Full report [pdf, 4 Mb] (Right-click and choose "Save Target As..." to save it on your computer)
   
  Contents [pdf, < 1 Mb] iii
  List of Authors [pdf, < 1 Mb] vii
  Preface [pdf, < 1 Mb] ix
  Executive Summary [pdf, < 1 Mb] xi
     
  Fraser River Sockeye 1
  1. Introduction [pdf, < 1 Mb] 1
    1.1 Motivation 1
    1.2 Authorship – North Pacific Marine Science Organization 2
    1.3 Organization of the Report 2
    1.4 Research Directed at Salmon in the Ocean 3
    1.5 General Biology 4
      1.5.1 Life cycle of sockeye salmon 5
      1.5.2 Spawning behaviour 7
      1.5.3 Migrations and habitat changes 7
      1.5.4 Ecotypes 9
      1.5.5 Production cycles 9
       
  2. Postsmolt Year [pdf, < 1 Mb]
11
    2.1 Postsmolt Migration Route
11
    2.2 Postsmolt Migration Timing
16
    2.3 Postsmolt Migration Speed 19
    2.4 Factors Affecting Postsmolt Migration Behaviour 19
    2.5 Postsmolt Feeding 20
    2.6 Postsmolt Growth 22
      2.6.1 Strait of Georgia 22
      2.6.2 Continental shelf 24
       
  3. Beyond the Continental Margin [pdf, < 1 Mb] 27
    3.1 Distribution and Migration 27
    3.2 Behaviour 31
    3.3 Feeding 33
    3.4 Growth 35
      3.4.1. Density-dependent growth (intra-specific) 35
    3.5 Thermal Limits to Oceanic Distribution 37
      3.5.1 Sockeye salmon in waters exceeding thermal limits 38
      3.5.2 Global climate model projections 41
         
  4. Maturation and Migration [pdf, < 1 Mb] 45
    4.1 Distribution of Maturing Fraser River Sockeye Salmon 45
    4.2 Diet and Feeding of Maturing Fraser River Sockeye Salmon 46
    4.3 Growth of Maturing Fraser River Sockeye Salmon 48
      4.3.1 Average size at age 48
      4.3.2 Trends 51
      4.3.3 Density-dependent growth (intra-specific) 53
      4.3.4 Density-dependent growth (inter-specific) 54
    4.4 Migration Behaviour and Timing 57
      4.4.1 Depth of migration 57
      4.4.2 Migration timing 58
    4.5 Landfall 61
    4.6 Northern Diversion 64
           
  5. Survival [pdf, < 1 Mb] 67
    5.1 Productivity and Survival 67
    5.2 Difficulties Estimating Salmon Abundance 68
    5.3 Smolt-to-Adult Survival 68
    5.4 Variability at Different Temporal Frequencies 71
      5.4.1 Interannual 71
      5.4.2 Decadal 72
      5.4.3 Evolutionary-scale 72
    5.5 Tag Recapture Rates as a Proxy for Survival 73
    5.6 Leading Indicators of Survival 73
      5.6.1 Comparisons with coho salmon survival 73
      5.6.2 Preliminary signs of 2010 abundance 75
           
  6. Oceanography and Climate [pdf, 1.5 Mb] 79
    6.1 Strait of Georgia 79
      6.1.1 Wind 79
      6.1.2 Fraser River discharge 80
      6.1.3 Surface water properties at lighthouses 82
      6.1.4 Hydrography at Nanoose station 86
      6.1.5 Nanoose Bay as an index of water properties in the Strait of Georgia 88
      6.1.6 Nutrients and chlorophyll 89
      6.1.7 Zooplankton 89
      6.1.8 Ichthyoplankton 89
      6.1.9 Temperatures in the Strait of Georgia in 2008 90
    6.2 Coastal Gulf of Alaska 91
      6.2.1 General description 91
      6.2.2 Queen Charlotte Sound 93
      6.2.3 Coastal biological oceanography beyond the Strait of Georgia 97
    6.3 Gulf of Alaska 101
      6.3.1 Large-scale climate processes 101
      6.3.2 Sea level pressure 102
      6.3.3 Ocean circulation 104
      6.3.4 Hydrography 104
      6.3.5 Physical spring in offshore Gulf of Alaska 107
      6.3.6 Nutrients 109
      6.3.7 Biological spring 110
    6.4 Extreme Sea Surface Temperatures 112
    6.5 Future of the Gulf of Alaska 113
      6.5.1 NEP ROMS model description 113
      6.5.2 Model sea surface temperature 114
           
  7. Discussion [pdf, < 1 Mb] 117
    7.1 Cause of Low Returns in 2009 117
      7.1.1 Data shortages 117
      7.1.2 Warm and cool in 2007 117
      7.1.3 Location of mortality 118
      7.1.4 The Harrison River anomaly 120
    7.2 Decline in Marine Productivity or Change in Distribution? 121
      7.2.1 Interpreting returns per spawner 121
      7.2.2 Gradual versus abrupt decline 123
           
  Acknowledgments [pdf, < 1 Mb] 129
  References [pdf, < 1 Mb] 131
     
  Appendices [pdf, < 1 Mb]  
  Appendix 1 North Pacific Marine Science Organization (PICES) 141
  Appendix 2 Terminology 143
  Appendix 3 Average age composition based on brood year returns to 2004 144
  Appendix 4 Comments on Pacific Salmon Commission workshop report 145
  Appendix 5 State of the Science 148
 
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