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Pink salmon estimation at Mission (2009 and 2011)

Pink salmon estimation at Mission (2009 and 2011) . March 28 th , 2012 Hydroacoustic Working Group Meeting. Overview. A brief history of pink salmon issues at Mission 2009 Sampling Geometry Mission based Total Salmon and Pink Estimates Cross River Distribution 2011

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Pink salmon estimation at Mission (2009 and 2011)

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  1. Pink salmon estimation at Mission (2009 and 2011) March 28th, 2012 Hydroacoustic Working Group Meeting

  2. Overview • A brief history of pink salmon issues at Mission • 2009 • Sampling Geometry • Mission based Total Salmon and Pink Estimates • Cross River Distribution • 2011 • Sampling Geometry • Sampling Considerations • Mission based Total Salmon and Pink Estimates • Cross River Distribution • Pink Run Sizes for 2009 & 2011 • Conclusion

  3. History Hydroacoustic programs on Fraser River Pink Salmon began in 1977. Various methodologies have been explored which employed mobile and fixed systems. Challenges were apparent early on and were quite different than for sockeye. • Migration is extremely near-shore and very dense. • Pinks are subject to extreme tidal fluctuations. • Pinks were believed to avoid the transecting Vessel. • Difficulties tracking individual fish targets.

  4. 1995-2005 • Preliminary investigations into boat avoidance in the near shore areas. • Observation of near shore and near bottom migration • Identification of tidal and daylight influence on the timing and abundance of upstream passage • Investigation into difficulties of tracking individual fish targets.

  5. 2005-2007 • Preliminary investigations into Didson and split beam estimation. • Near-field blocking of split beam. • Didson technology was used to quantify the effects of boat avoidance near-shore. • Quantify the extent of the tidal influence on upstream passage. • Identified mechanisms of bias in the near-field effect of the transducer and associated tracking bias.

  6. 2009-2011 • Refinements in the methodology. • Extending the fence, reducing near-field blocking. • Incorporation of DIDSON counts in the estimates.

  7. Pink Migration during September Bias associated with test fishing sampling is minimized: • In September, estimates of species composition are strongly skewed to Pinks: >95%. • Cannot separate up-river and lower river stocks so we are only concerned with a total pink estimate. Can concentrate on the hydroacoustics technology and sampling design rather than outside influences.

  8. 2009

  9. In-season Sampling Design –2009 September Inseason Total Salmon Estimate: 5.0 Million Mobile-Split-beam Left Bank-Split-beam 70 m 300 m

  10. Post Season Estimates 2009 September Inseason Total Salmon : 5.0 M 6.7 M 16 M + RB D2 + LB D1 Mobile-Split-beam RB-D2 LB-S1 LB-D1 20 m 10 m

  11. Total Salmon 2009 - September QualarkTotalSalmon: 6.7M

  12. 2009 Pink Estimations -September QualarkTotalPink: 5.8M

  13. Cross River Distribution - 2009 September Daily Distribution September Total Distribution 79% 11% 10% 70 m 280 m 10 m

  14. 2011

  15. In-season Sampling Design 2011 September Inseason Total Salmon Estimate: 10.4 Million Left-bank area Right-bank area Off shore area Mobile-Split-beam RB-D2 LB-S1 60 m 300 m 20 m

  16. Post-season Estimates 2011 September Inseason Total Salmon : 10.4 M 11.5 M 14.3 M + RB D2 &D3 + LB D1 Mobile-Split-beam LB-S1 LB-D1 RB-D2 RB-D3 LB-D4 20 m 40 m

  17. DIDSON Count Methodology • Count all fish targets regardless of size • Measure fish lengths from sub-sampled DIDSON data. • Run a mixture model to determine the percent of salmon size targets. • With priors of salmon fork-lengths from test-fishing samples • Priors of several species (resident fish, pink, sockeye, chinook) • Remove non-salmon size targets from the net upstream DIDSON count.

  18. Mixture Model Analysis Portions Small fish: 0.2 Pink: 0.64 Sockeye: 0.14 Chinook: 0.02

  19. Total Salmon 2011 - September QualarkTotalSalmon: 4.7M

  20. 2011 Pink Estimations -September QualarkTotalPink: 4.2M

  21. Cross River Distribution - 2011 September Daily Distribution September Total Distribution 79% 11% 10% 10% 70 m 300 m 40 m

  22. Pink Run Size (Above Mission) (All Areas) (Mission Based Estimate)

  23. Distribution of the Escapement 2009 2011

  24. Conclusion: • We believe we can produce a better estimate of the total return of Fraser Pink salmon than the current estimation method which is from the purse seine test fishery. • Advantage of a Mission based pink estimate is that we can update the purse seine expansion line. • Time management: • Not able to produce an estimate real time as we are not able to keep up with DIDSON counts in-season. • Cost: • To produce this estimate we need to operate a minimum of 2 DIDSON systems. • It took 4 months working full time on DIDSON counts and measurements to complete the work necessary to produce an estimate.

  25. End

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