Fraser River sockeye salmon: data synthesis and cumulative impacts

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12-31% of the diet. The evidence presented by Andrew Trites at the Cohen Commissionworkshop suggests that salmon comprise approximately 10% of the overall diet of Stellersea lions.15. Page 52 - insert "Strait of Juan de Fuca" after "Queen Charlotte Strait". Also, youneed a map labelling these salt-water locations, as well as the "Queen Charlotte Sound"mentioned on page 57.Response: Corrected as suggested. We have added labels to Figure 3.3-2 for the major saltwaterlocations commonly referred to throughout the report.16. Top of page 53 - The following example of potential predation effects is veryimportant: "...if 0.1% of the diet of spiny dogfish was sockeye smolts, they wouldconsume 14.5 million smolts within the Strait of Georgia (very significant predation)...".Analogous examples for marine mammal predators, particularly Steller sea lions, areconspicuous by their absence. This omission must be corrected here, as well as onpage 50 and the bottom of page 54.Response: Agreed, and implemented. We have added greater discussion regarding Stellersea lions in Sections 4.4 and 4.5.17. Page 57 - The paragraph under the heading "Conditions in Queen ..." correctlycharacterizes the different conclusions about the role of marine conditions "outside" ofVancouver Island compared to "inside" that were drawn by the current report and thereport from the PSC workshop in June of 2010.Response: Thank you.18. Page 58 - Everything from the first line "Three model sets were tested ..." to the endof this section at "... drivers examined" needs to be thoroughly re-written because it isvery confusing, uses undefined terms such as "global model" and "model sets", anddoes not even mention which dependent variable the models are trying to explain! I hadto re-read this page and a half several times to deduce, for example, what "model sets"meant. Here it appears that one could simply substitute the word "period" for "modelsets", because the term seems to imply models that were analyzed across three timeperiods. However, if you make that substitution here, it will be at odds with how "modelsets" are used on pages 78-79. I purposely did not yet read Appendices 3 and 4, so thatI could comment on how understandable this section was without reading the detailedmethods in those appendices. Unfortunately, this section does not work as it stands.Fortunately, the text on pages 58-59 can be helped considerably by inserting a tablethat indicates in words (not in equations) which independent or predictor variables areused in each model and for which time periods data on those variables were available.The text above the table should at least state whether you are using a multiple linearregression or some other form of statistical model.126
Response: This section has been completely rewritten, and we have introduced ourquantitative methods in plain language in section 3.3.6.19. Page 60 - The exceptional case of the Harrison River sockeye should be movedfrom its current hidden location at the end of point 4 and put into its own point. This willenable you to emphasize the importance of the evidence that could be gleaned fromstudying that stock more thoroughly, given that its life history is quite different from otherFraser sockeye stocks.Response: We have moved comments on the Harrison stock into their own bullet point toemphasize that stock-specific knowledge of its migration route and timing would beespecially useful given its unique life history and productivity trends (i.e., the only stockwith increasing productivity).20. Page 61 - I would add a new point under "Key things we need to know better" thatwould specifically state the need to take the current knowledge about consumption ratesof sockeye salmon and other species by marine mammals, the bioenergetics of thosemammals along with their population sizes, and combine these into estimates of totalconsumption of sockeye salmon by populations of a given species of marine mammal.For too long now, this last step has been missing, yet it should be easy to calculate arange of estimates given a standard set of assumptions like those that Christensen andTrites apparently used for their spiny dogfish example described on page 53.Response: We agree with the reviewer’s comment and have added this recommendationunder “Key things we need to know better”. This recommendation has the advantage ofbeing fairly specific and preliminary efforts could be initiated immediately with theinformation currently available.21. In the context of the previous comment, lines 8-10 on page 62 make a statementthat is inconsistent with the point made on page 53 about the total potential impact ofspiny dogfish predation on salmon, despite salmon being a tiny portion of the diet of thedogfish. The offending sentence is: "On the return journey back to the Fraser, there aremany marine mammals that will prey on adult salmon, but sockeye salmon do notappear to be a substantial portion of any of their diets". Surely, the authors have to beconsistent in their logic and say the same thing about the marine mammals as they didfor the spiny dogfish.Response: We have revised this section.22. The line in Figure 4.5-2 does not seem to be the best-fit line; visually at least, itseems like it should have a lower slope. What was the assumption about the error termin the fitting method?Response: This graph was extracted as an image from the publication cited and thereforethe “trend” line could not be removed. We were not able to acquire the underlying data127
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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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feel reasonably confident in this c
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Nelitz et al. (2011; Table 18) foun
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in the Lower Fraser than other Fras
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stressors. Thus our conclusions hav
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There are many marine predators tha
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assumption that exposure occurs whe
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observations that are then averaged
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Johannes et al. (2011) demonstrate
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“likely” contributor to the ove
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Table 4.4-2. Model specifications f
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Region Variable M1 M2 M3 M4 M5 M6 M
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3. survival rates within key portio
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2011). The thermal limit hypothesis
Page 91 and 92: Historically, the majority of retur
Page 93 and 94: salinity. There is much evidence th
Page 95 and 96: declines (discussed in section 4.2
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
Page 115 and 116: will likely have a high correlation
Page 117 and 118: 5.0 Conclusion5.1 Important Contrib
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
Page 134 and 135: utilized to clarify the full range
Page 137 and 138: Appendix 2. Reviewer Evaluations an
Page 139 and 140: the conclusions of the Expert Panel
Page 141: Response: Figure numbers have been
Page 145 and 146: ased on time or other stocks) to
Page 147 and 148: them in terms of how changes in spa
Page 149 and 150: efer to some variable being include
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
Page 167 and 168: Response: We have further emphasize
Page 169 and 170: 5. I would also encourage the autho
Page 171 and 172: events occur, it should be possible
Page 173 and 174: I don’t have anything to add beyo
Page 175 and 176: constitutes an exposure to human ac
Page 177 and 178: 3.3.1 has been revised to say “As
Page 179: most likely contributors to the rec
Page 182 and 183: A3.2.1 Integrative quantitative met
Page 184 and 185: Table A3.3-1. A summary of data set
Page 186 and 187: ProjectNumber Project Name Variable
Page 188 and 189: ProjectNumber Project Name Variable
Page 190 and 191: 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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