Fraser River Sockeye Fisheries and Fisheries Management - Cohen ...

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Stock MAPEReturn Explainedby Forecast (R 2 )RegressionSlopeRegressionIntercept(# fish)Run sizerelative tototal FraserInterpretation Reliability: Relationship between forecast and return is statisticallysignificant, thus forecast is reliable. Expect forecast to overestimate orunderestimate return by 39% in any given year.Summer 39% 30%0.64(significant)notsignificant56.6% Precision: Moderate/Small amount of inter-annual variationexplained by forecasts (R 2 = 0.30). Accuracy: Slope departs mildly from one and intercept is notsignificantly different from zero, thus long-term accuracy is good butlarge forecasts tend to underestimate returns.LateSummer27% 74%0. 87(significant)notsignificant31.1% Reliability: Relationship between forecast and return is statisticallysignificant, thus forecast is reliable. Expect forecast to overestimate orunderestimate return by 27% in any given year. Precision: Large amount of inter-annual variation explained byforecasts (R 2 = 0.74). Accuracy: Slope is close to one and intercept is not significantlydifferent from zero, thus long-term accuracy is good.79
Despite the significant predictive power of forecasts for the four run-timing groups, thereremains substantial unexplained error in actual return sizes. As noted above, Fraser Riverforecasts explained 44% of the year-to-year variation in returns between 1980 and 2009(i.e., leaving 56% unexplained), and we can expect returns in any given year to vary fromforecasts by about 25%. Forecasts seem to be best for the Early Stuart and Late-runtiming groups with 76% and 74% of the annual variation explained, respectively;whereas forecasts have been weaker for Early Summer and Summer-run groups whereforecasts have accounted for 23% and 30% percent of the annual fluctuation.The recent large errors in Fraser sockeye forecasts and recognized challenges withforecasting salmon returns have led most managers to rely on in-season information tomanage sockeye fisheries. Fishermen and processors want reliable forecasts so they canmake better business decisions, but most recognize that they should not make majorinvestments based on annual run size forecasts. Importantly, our trend analysis is basedon historical data and may have limited ability to predict the future reliability of forecastsfor a particular stock, especially if changing environmental conditions undermine theutility of even the best performing pre-season forecasts based on historical data; yetanother reason why pre-season forecasts are of little use in the management of Frasersockeye and many southern B.C. salmon stocks.Overview of In-season Run-size Abundance EstimationOur evaluations related to escapement enumeration address the following task as definedin the initial Statement of Work:3.10 The Contractor will describe and evaluate the accuracy, precision andreliability of in-season run-size abundance estimation methods. This work willinclude a description of the application of in-season and post-season run-sizeabundance estimation in harvest management.In-season assessments of returning run size are conducted by the PSC using a variety ofmodels. These models integrate historical information on run timing with data from thefour primary in-season data collection programs: (1) catch estimation, (2) test fishing, (3)stock identification, and (4) escapement estimation. The catch monitoring programsdescribed earlier in this report provide in-season catch estimates for each of the majorfisheries. Seine and gillnet test fisheries are conducted on both potential approach route(Johnstone Strait and Juan de Fuca Strait) to obtain indices of abundance and biologicalsamples (scales and DNA) for racial analysis. Biological samples from commercial and80
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Fraser River Sockeye Fisheriesand F
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EXECUTIVE SUMMARY1. Catch Monitorin
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implement harvest rate ceilings to
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Table of ContentsEXECUTIVE SUMMARY
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List of TablesTable 1 Annual estima
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List of FiguresFigure 1 Fraser sock
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Figure 21 Estimates of total catch,
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List of AppendicesAppendix A Statem
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used to (1) estimate catch for each
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FISHERIES HARVESTINGOverview of Fis
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Figure 1 Fraser sockeye marine migr
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Table 2 Summary of available inform
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Table 3 provides the annual estimat
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Table 4 Summary of available inform
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season update teleconference meetin
Page 32 and 33: Catch Estimation MethodsThe procedu
Page 34 and 35: catch estimates was detected using
Page 36 and 37: of precision. The overall rating fo
Page 38 and 39: 1998-00 - No agreements with Sto:lo
Page 40 and 41: initiation of the AFS Agreements in
Page 42 and 43: Table 12 Comparison of annual socke
Page 44 and 45: Table 13 Annual estimates of the ha
Page 46 and 47: Canadian Commercial FisheriesThe pr
Page 48 and 49: logbook systems. In addition to the
Page 50 and 51: Table 15 Fraser River sockeye salmo
Page 52 and 53: Available catch estimates for the r
Page 54 and 55: Table 17 Summary of available infor
Page 56 and 57: anged from less than 100 to over 30
Page 58 and 59: Washington State Recreational Fishe
Page 60 and 61: equirements have been applied to se
Page 62 and 63: salmon were biopsied or tagged with
Page 64 and 65: Stellako-Late Stuart and 531 Adams)
Page 66 and 67: FISHERIES MANAGEMENTOverview of Pre
Page 68 and 69: parents of the recruits). Effective
Page 70 and 71: within the confidence limits. For e
Page 72 and 73: Ratio of Return to Forecast5.04.03.
Page 74 and 75: Ratio of Return to Forecast5.04.03.
Page 76 and 77: Table 20 Pre-season forecast models
Page 78 and 79: different from the straight line),
Page 80 and 81: Prediction ability of ForecastsProp
Page 84 and 85: test fisheries are analyzed in-seas
Page 86 and 87: Inputs to the cumulative-normal mod
Page 88 and 89: eginning of the runs, but by mid-ru
Page 90 and 91: Median Absolute Percent Error (1997
Page 92 and 93: variety of hydroacoustic techniques
Page 94 and 95: enefited from improved technologies
Page 96 and 97: Post-season estimates of Escapement
Page 98 and 99: precision achieved was considerably
Page 100 and 101: m 3 /sec during the sockeye run. Fi
Page 102 and 103: Escapement TargetsOur evaluations r
Page 104 and 105: 20% of the average of the 4-year se
Page 106 and 107: Table 24 Low escapement benchmarks
Page 108 and 109: Table 25 Comparison of post-season
Page 110 and 111: fisheries have been permitted to ta
Page 112 and 113: sub-dominant cycle years (e.g., 200
Page 114 and 115: SummaryLow Escapement Benchmarks (L
Page 116 and 117: Extent of OverharvestingThe estimat
Page 118 and 119: 2,000,0001,800,000Early StuartCatch
Page 120 and 121: Cultus Lake Sockeye Recovery Effort
Page 122 and 123: Figure 23 Number of adult sockeye e
Page 124 and 125: Recovery ObjectivesIn anticipation
Page 126 and 127: 2008 the escapement estimate was 34
Page 128 and 129: BRISTOL BAY, ALASKA SOCKEYE FISHERY
Page 130 and 131: accurate, precise, and timely, (2)
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The Bay is subjected to large tidal
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activity (Bocking and Peterman 1988
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% of total run45%40%35%30%25%20%15%
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Harvest estimation methodsTotal har
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Millions of sockeyeYearFigure 27 Hi
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management structure complements th
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1.5Togiak4.03.5NushagakMillions of
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Millions of sockeye7.06.05.04.03.02
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logical given the dynamics of the r
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1.61.4Number of fish (millions)1.21
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Pre-season forecastsAs noted above,
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8.0y = 0.79x + 1.59R² = 0.417.8Log
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12010080MAPE60402001971-1980 1981-1
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Median percent error (MPE)3020100-1
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Table 28 Average age composition of
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dampeners to reduce surface turbule
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current year’s run is accounted f
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and 1999 Revised Annexes. This inte
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Bristol Bay was in 1997 when there
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upon by managers to determine when
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STATE OF THE SCIENCECatch Monitorin
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2006) due to concerns regarding the
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RECOMMENDATIONS1. DFO needs to ensu
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LITERATURE CITEDAdkison, M.D. and R
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Beacham, T.D., M. Lapointe, J.R. Ca
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CSAS. 2007 Pre-season run size fore
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Evans, D.G., J.B. Browning and B.G.
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Hardie, D.C., D.A. Nagtegaal, K. He
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Pacific Salmon Commission. 1998. Re
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Robichaud, D., J.J. Smith, K. K. En
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Valderrama, D. and J.L. Anderson. 2
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Appendix A Statement of Work.Cohen
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All sectors3.7 The Contractor will
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“State of the Science”. Comment
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3.3 The Contractor will review and
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Appendix BList of requests to DFO b
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DFO Request 15: Recent CSAS documen
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Item Description DateRequestedReque
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Appendix CFirst Nation catch monito
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Table C-1 Summary of information re
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Table C-2 Weekly catch monitoring e
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Table D-1 Summary of information re
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community of Port Renfrew. The area
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IPrecision ( + % of the estimate)10
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Table E-2 Annual Strait of Georgia
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Table E-4 Annual Johnstone Strait e
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Table E-6 Lower Fraser River recrea
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0 would mean that the forecast does
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the general ups and downs of the ob
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Appendix G Graphical representation
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Early Stuart Timing GroupEarly Stua
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Summer-run Timing GroupSummer run7.
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Fraser River Indicator Stocks (list
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Appendix H Pre-season forecast: sum
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ManagementGroup(IndicatorStock)MAPE
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ManagementGroup(IndicatorStock)MAPE
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Appendix I Methods of In-season Sto
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Marine Gillnet Test FisheriesThe gi
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Expansion line (x1000)9080706050403
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Table I-2 Mean values for purse sei
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Figure I-5 Map of test fishing loca
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Appendix J The Hydroacoustics progr
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An SEF project was secured in 2007
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Conservation action Comments Partne
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Table K-2 Summary of actions to rec
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Table L-1 Catch and escapement of s
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Table L-3 Performance criteria of p
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Ratio of annual return to the avera
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Appendix M Reviewer comments on the
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Request #5: Sockeye allocations by
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utility of pre-season forecasts. Pr
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3. Are there additional quantitativ
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made via tagging and experimentatio
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Page 60: The authors make extensive
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ensure the reader does not assume t
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The reported excerpts from Bradford
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(budgets, legal issues, pseudo-cons
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REVIEW 3/3Reviewer Name: Dr Sean Co
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season forecasts that eventually co
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allocation shows "No agreement", an
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size.Figures showing errors for pre
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Goals can easily generate confusion
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Total rows from all these tables be
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Exploitation Rate100%90%80%70%60%50
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Exploitation RateEarly Stuart90%80%
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