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

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variety of hydroacoustic techniques and gillnet test fishery data to determine speciescomposition of the hydroacoustic target counts. Since 1992, differences between Missionestimates and the sum of spawning escapement and catch above Mission have beenattributed to “en-route loss”. In 2006, the number of Late-run sockeye in spawning areasabove Mission was estimated to be more than twice the Mission escapement estimate.Such major discrepancies have recently undermined the confidence in the in-seasonescapement estimates and have led to the development of alternative in-seasonmonitoring systems using DIDSON hydroacoustic techniques at Mission and Qualark forfish counts and fishwheels to estimate near-shore species composition.Post-season escapement estimates are believed to be much more reliable for Frasersockeye because over 75% of the spawning sockeye have been enumerated usingintensive mark-recapture techniques or counting fences (Table 22). The remainder isenumerated using visual survey techniques combined with expansion factors thattypically underestimate the escapement for smaller stocks.Table 22 Summary of the accuracy, precision and reliability of mark-recapture,fence count and visual survey methods used to obtain post-season estimatesof spawning escapement for Fraser sockeye.% of Quality of Escapement EstimatesMethods Total Accuracy Precision Reliability1980-2005 12006-2009 2Mark-recapture 63% Likely good < +25% HighFence Counts 14% Very good High HighVisual 23% Likely biased low Unknown MediumMark-recapture 64% Good +3-23% HighFence Counts 14% Very good High HighVisual 22% Biased low Unknown MediumTotal Good Medium High1 Schubert and Houtman (2007)2 Preliminary Annual Fraser Sockeye Escapement Reports (Keri Benner, DFO Kamloops, pers. comm.)Aside from a few streams that are enumerated using unbreached fence counts, theaccuracy of the post-season escapement estimates is unknown. Precision can beestimated for all mark-recapture estimates and tend to be in the ±5 to 25% range (for 95%confidence intervals). The reliability of the escapement estimates vary substantially fromstream to stream and between salmon species but Fraser sockeye escapement estimates89
tend to be among the most reliable escapement estimates derived for any B.C. salmonstock.In-season Escapement MonitoringA variety of monitoring systems are used in the lower Fraser River to assess the in-seasonabundance and stock composition of sockeye as they escape from the marine fisheries.These systems include: (1) Cottonwood drift gillnet test fishery; (2) Whonnock driftgillnet test fishery; (3) Mission hydroacoustic site; and (4) Qualark hydroacoustic site.Whonnock and Cottonwood test fisheries are used occasionally to estimate the upstreampassage of sockeye during (1) the Early Stuart time period if the salmon abundance in theriver is too low and variable to justify the Mission Hydroacoustics program, and (2) thePink migration in September in odd-years when sockeye are caught in low butdisproportionate numbers to Pink salmon. Since the mid-1990s, test fishery catches havebeen impacted severely by salmon predators such as harbour seals. Some mitigation ofthe predation and interference by seals has been achieved through the use of anexperimental pulsed, low-voltage DC electric gradient (Forrest et al. 2009).The Cottonwood Test Fishery is conducted at a site in the south arm of the Fraser Riverthat is approximately 20 km upstream from Steveston, B.C. An index of sockeyeabundance entering the Fraser River is obtained from a single 5-9 minute drift gillnet setmade during slack tide each day. Scale and DNA samples are obtained from a portion ofthe sockeye caught each day.The Whonnock Test Fishery is conducted on the Fraser mainstem at a location 48 kmupstream from Cottonwood and 18 km downstream from the Mission hydroacoustic site.This test fishery conducts two 5-10 minute sets per day using a variable-mesh nonselectivegillnet. The primary purpose of this test fishery is to provide species and stockcomposition estimates that can be applied to the Mission hydroacoustic counts to derivestock specific estimates of the number of sockeye passing Mission each day.Mission Hydroacoustic SystemPSC has operated a hydroacoustic facility on the Fraser River near the Mission Bridgesince 1977, for the purpose of providing timely in-season estimates of sockeyeescapement from marine and lower river fisheries (Appendix J). This program has90
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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
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Catch Estimation MethodsThe procedu
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catch estimates was detected using
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of precision. The overall rating fo
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1998-00 - No agreements with Sto:lo
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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 82 and 83: Stock MAPEReturn Explainedby Foreca
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 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)
Page 132 and 133: The Bay is subjected to large tidal
Page 134 and 135: activity (Bocking and Peterman 1988
Page 136 and 137: % of total run45%40%35%30%25%20%15%
Page 138 and 139: Harvest estimation methodsTotal har
Page 140 and 141: 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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