Fraser River sockeye salmon: data synthesis and cumulative impacts

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Table 4.8-1. Other factors potentially contributing to the decline of Fraser River sockeye salmon that were notconsidered within the spectrum of Cohen Commission technical reports. Some of these items are relatively focusedquestions whereas others are very broad. The list order does not represent any prioritization.FactorVolcanic AshCompetition withPink Salmon*Hatchery FishHatchery FishCompetitors andFood ResourcesQuestion of InterestDid the 2008 eruption of the Kasatochi volcano in Alaska contribute to the record sockeye returns in 2010 byproviding a natural fertilization of the ocean that resulted in greater growth and ultimately higher survival rates?Do odd-year pink salmon (the dominant cycle) compete with sockeye salmon for food resources during theirmigration overlap, resulting in diminished resources for sockeye salmon and therefore lower survival rates?Do large releases of hatchery fish result in increased predation of wild fish by creating high, localizedconcentrations of prey that attract increased numbers of predators to a place where wild and hatchery fish aremixed?Do large releases of hatchery fish affect ocean survival of wild fish through competition or predation?Have sockeye survival rates been reduced by increased competition for resources resulting from increasedabundance of competitors and/or reduced food resources?Early Outmigration Have sockeye smolts been leaving lakes earlier, driven by changing climate and climate associated factors(e.g., lake thaw), then arriving “too early” to an ocean environment with insufficient resources because thephenology of key ocean characteristics has not advanced by nearly as much ?Nursery LakeFood SupplyUnreportedFishing*Has the quantity and quality of planktonic food required to maintain historical sockeye productivity declined asa result of climate change?Could unreported catches of sockeye on the high seas and in fisheries outside of the Pacific Salmon Treatyfisheries have contributed to Fraser sockeye productivity declines?* Competition with pink salmon and unreported fishing were addressed in the PSC report (Peterman et al. 2010). Evidence in Peterman et al.(2010; Section 4.9) is consistent with the hypothesis that odd-year pink salmon from Alaska and Russia compete with returning adult Frasersockeye (Stage 4 in this report). Unreported catch is unlikely to have contributed to Fraser sockeye productivity declines (Peterman et al. 2010;Section 4.1).100
5.0 Conclusion5.1 Important Contributors to the Decline of Fraser River SockeyeWe present our conclusions for each life history stage, recognizing that there are interactionsboth within and between life history stages. These results do not consider aquaculture (report inprogress) or other factors not considered by the Cohen Commission.Stage 1: Incubation, Emergence and Freshwater RearingWith the exception of climate change, which we consider to be a possible factor, and pathogens(for which no conclusion is possible due to data gaps), it is unlikely that the other factorsconsidered for this stage, taken cumulatively, were the primary drivers behind long term declinesin sockeye productivity across the Fraser Basin. These factors included forestry, mining, largehydro, small hydro, urbanization, agriculture, water use, contaminants, density dependentmortality, predators, and effects of Lower Fraser land use on spawning and rearing habitats.We feel reasonably confident in this conclusion because juvenile productivity (which integratesall stressors in this life history stage except over-wintering in nursery lakes) has not declinedover time in the eight of the nine Fraser sockeye stocks where it has been measured. We wouldbe even more confident if more stocks had smolt enumeration rather than fry estimates (onlyChilko and Cultus stocks have smolt estimates). Though not primary drivers of the Frasersockeye situation, each of these factors may still have had some effects on some Fraser stocks insome years (the data are insufficient to reject that possibility). We suspect, based on qualitativearguments alone, habitat and contaminant influences on Life Stage 1 were also not the primarydrivers responsible for productivity declines occurring to most non-Fraser stocks assessed byPeterman and Dorner (2011). However, given the absence of any exposure data and correlationanalyses for non-Fraser stocks, it is not possible to make conclusions on the relative likelihoodsof factors causing their declining productivities. None of the factors considered for Stage 1 arelikely to have been much worse in 2005 and 2006 for Fraser sockeye stocks, sufficient to havesignificantly decreased egg-to-smolt survival in the salmon that returned in 2009. Similarly, noneof these factors are likely to have been much better in 2006 and 2007, sufficient to havesubstantially improved egg-to-smolt survival in the salmon that returned in 2010.Stage 2: Smolt OutmigrationWe analyzed the same factors for Stage 2 as for Stage 1 and came to the same conclusions. Thereare however three key differences in our analyses for these two stages. First, regardless ofdifferences in their spawning and rearing habitats, all sockeye stocks pass through the highly101
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April 2011technical report 6Fraser
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Stage 2: Smolt OutmigrationWe analy
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of multiple stressors and factors,
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4.3.5 Other evidence ..............
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List of TablesTable 4.2-1. Evaluati
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List of FiguresFigure 2.3-1. Cumula
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these integrative frameworks, conve
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2.0 Cumulative Impacts or Effects2.
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assumed that there is no potential
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classes of stressors. However, if s
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affected by many stressors over its
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examples illustrate this problem --
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possibly even negligible component
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Figure 3.3-1. The conceptual model
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3.3.3 Life history perspective/appr
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additional analyses to gain further
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Figure 3.3-3. Flow diagram used to
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This project is unusual in its scop
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4.0 Results, Synthesis and Discussi
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Peterman and Dorner (2011) have thr
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Figure 4.1-3. Estimates of long ter
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Figure 4.1-5. A) Total run size of
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Figure 4.1-6. Aggregate returns to
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o were generally worse during the l
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Freshwater predators on juvenile so
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copper, iron, mercury and silver).
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Several analyses by MacDonald et al
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abundances (Sproat, Klukshu, Chilka
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Page 67 and 68: Nelitz et al. (2011; Table 18) foun
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Page 71 and 72: stressors. Thus our conclusions hav
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Page 75 and 76: assumption that exposure occurs whe
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Page 83 and 84: Table 4.4-2. Model specifications f
Page 85 and 86: Region Variable M1 M2 M3 M4 M5 M6 M
Page 87 and 88: 3. survival rates within key portio
Page 89 and 90: 2011). The thermal limit hypothesis
Page 91 and 92: Historically, the majority of retur
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Page 97 and 98: There is indisputable evidence of t
Page 99 and 100: Figure 4.6-2. Number of years that
Page 101 and 102: correlation was statistically signi
Page 103 and 104: 4.6.7 Key things we need to know be
Page 105 and 106: al (2010). The combined effect of a
Page 107 and 108: more likely to suffer en-route and
Page 109 and 110: Table 4.7-2. Variables included in
Page 111 and 112: However, an important limitation is
Page 113 and 114: Alternative PreyVariablesModelsM1 M
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Page 119 and 120: Stage 5: Migration back to SpawnWhi
Page 121 and 122: More specifically, the extended res
Page 123 and 124: The twelve highest priority recomme
Page 125 and 126: Life stagefor FraserRiversockeyesal
Page 127 and 128: 6.0 ReferencesAinsworth, L.M., Rout
Page 129 and 130: Johannes, M.R.S., R. Hoogendoorn, R
Page 131: Schaller et al. 2007. Comparative S
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Page 137 and 138: Appendix 2. Reviewer Evaluations an
Page 139 and 140: the conclusions of the Expert Panel
Page 141 and 142: Response: Figure numbers have been
Page 143 and 144: Response: This section has been com
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Page 147 and 148: them in terms of how changes in spa
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Page 151 and 152: ... (Table xx)". Structures of thes
Page 153 and 154: Report Title: Fraser River sockeye
Page 155 and 156: show stronger correlations. Hence,
Page 157 and 158: Fraser and non-Fraser sockeye popul
Page 159 and 160: a single database for other researc
Page 161 and 162: Response: We have removed the itali
Page 163 and 164: evidence unique to each life stage.
Page 165 and 166: Report Title: Data Synthesis and Cu
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Response: We have further emphasize
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5. I would also encourage the autho
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events occur, it should be possible
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I don’t have anything to add beyo
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constitutes an exposure to human ac
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3.3.1 has been revised to say “As
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most likely contributors to the rec
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A3.2.1 Integrative quantitative met
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Table A3.3-1. A summary of data set
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ProjectNumber Project Name Variable
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ProjectNumber Project Name Variable
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A3.4 Data PreparationContractor dat
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Table A3.4-2. An example entry in t
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Table A3.4-5. Brood year adjustment
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Table A3.4-7. Example output from t
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Table A3.4-9. The table of contents
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ProjectNumberProject Variable Subse
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The objective of our approach is to
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investigated ecosystems” (Burkhar
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Figure A3.5-1. Flow diagram used to
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multiple stresses simultaneously. T
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Change point analysis of productivi
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Figure A3.5-1. This is an example o
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ecruits for this analysis as we wan
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exclude covariates with limited yea
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Figure A3.5-3. Average chlorophyll
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Status only data setsIn many cases
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The A-series of model sets based on
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with this report given the vast sco
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Table A3.5-5. Example of the model
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categories of stressors. We cannot
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o In some cases it may be the timin
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Appendix 4. Quantitative ResultsA4.
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alance” over time and so this it
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Figure A4.2-3. Stock composition fo
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Figure A4.2-5. Stock composition fo
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A4.3 Multiple Regression ResultsA4.
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Life stage Stressor category Variab
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The results show strong support for
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ModelSet_A4c_VarName M1 M2 M3 M4 M5
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Table A4.3-7. Estimates for all fix
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A4.3.3Analyses by stressor category
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Table A4.3-10. Estimates for all fi
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Model: B4bBrood years: 1969-2001We
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A4.3.4Analysis by regionModel: C4a1
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suggest any underlying mechanism, b
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Model: C1a1996-2004For 1996-2004, i
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Table A4.3-23. SoG C1a candidate mo
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Appendix 5. Data Template User Guid
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Metric Connected to Biologically-su
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Initial Conceptual Model (Worksheet
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Commentsopen again. It is acceptabl
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Appendix 6. Workshop Report 1 (Nov.
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Table of ContentsTable of Contents
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PresentationsProductivity Dynamics
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and scope for improvement, particul
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Workshop participants pointed out t
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o Can you find the same shared tren
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generally better for Alaska sockeye
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Relative Likelihood of Alternative
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There was widespread agreement with
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Appendix A: List of Projects and In
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Peer Reviewers: Provide constructiv
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MacDonald Environmental Sciences Lt
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Appendix C: Workshop MinutesContent
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Levy urged researchers to bear in m
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within-population, within-brood-yea
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To address potential skepticism ove
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instead of migrating directly out i
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considered a good surrogate of temp
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Bristol Bay review: There are subst
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Method: The approach included formu
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Staley: Our project needs to compar
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Levy: It will go ahead in January.
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preliminary assessment of potential
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MacDonald: We’re waiting for all
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including Shuswap and North Thompso
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and biological variables. The combi
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temperatures. Notably, it doesn’t
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Seasonal population distribution pa
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Information gaps: The most importan
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Fraser sockeye salmon habitat analy
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survey data, but they were looking
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was also shown that tagged fish ret
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English: There was extensive holdin
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periods showed that 4 to 6 stocks (
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Q/A: Researchers should also feel f
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Peterman: We’re lacking the big p
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Appendix D: Table of likelihood/ hy
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Fraser River sockeye salmon: data synthesis and cumulative impacts

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