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Adult Steelhead Abundance Estimates Based on PIT Tag Arrays in Idaho. Rick Orme, Nez Perce Tribe Department of Fisheries Resources Management and Chris Beasley and Jody White Quantitative Consultants. Background. The Integrated Status and Effectiveness Monitoring Project (ISEMP).
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Adult Steelhead Abundance Estimates Based on PIT Tag Arrays in Idaho Rick Orme, Nez Perce Tribe Department of Fisheries Resources Management and Chris Beasley and Jody White Quantitative Consultants
Background The Integrated Status and Effectiveness Monitoring Project (ISEMP) • Design, implement, test, and evaluate Status and Trends and Effectiveness Monitoring programs for salmon and steelhead populations and habitat. • Determine whether innovative methods can be employed to increase the accuracy and precision of juvenile and adult abundance estimates at the subpopulation, population, and major population group (MPG) scales. • Anadromous Monitoring Strategy: high precision abundance data for at least one population per MPG.
PIT Tag Array • In-stream antennas
Existing ISEMP arrays
Methods LGD sampling Population Estimated # Sampled & Tagged PIT tags Number / Estimate Ratio (Expansion Factor) - Systematic sample - Consistent sample rate Date
Methods Population estimate using arrays Array 1 Array 2 C = Captures R = Recaptures M= Marks ESCAPEMENT = MC/R
Precision Starting Population Estimate, (complex) Sample rate and adjustment, SbyC fish, August & December passages, fall back, --- adapt fall Chinook run reconstruction methodology Estimated Number of PIT Tags Variables Response Variable Model Escapement 4 levels CV Percent Tagged 4 levels Efficiency 5 – 99% = SE / Mean Conversion 5 – 99%
Precision CV of Escapement Stream Escapement = 250 Tag Ratio = 15:1 (6.7%)
Precision 35 0.05 Escapement = 250 30 Escapement = 2,000 0.04 25 0.03 20 CV of Escapement Estimate Number of Recaptures 15 0.02 10 0.01 5 0.00 0 0 2 4 6 8 10 12 14 16 Percent of Population PIT Tagged Efficiency = 90% Conversion = 90%
Assumptions • PIT Tags Representative of Population • Sub-sample (LGD) • Systematic with a consistent sample rate • Pre-array • Tag loss, tag induced mortality • Mark-recapture • Mark loss, missed marks, equally capture prob., equal mortality, random mixing, no additions, # recaptures
Project Status • Installed arrays in 2009 • Initiated adult tagging fall 2009 • Patiently waiting for adults
3D9.1BF2328B20 3D9.QBF1641BB4 3D9.1UF1955DD2 3D9.1BE1970B60 3D9.1BFS971444 3D9.1BF1TE288A 3D9.1BF1AI1964 3D9.1BF232OD0D 3D9.1BF2330NF0 3D9.1BF236AFS8 3D9.1BF23884D? 3D9.1BF23A0EB4 Acknowledgments BPA provided funding Chris Beasley, Jody White Bill Young, Jason Vogel