Bryce Glaser Dan Rawding

(WDFW)

Biological Reference Points (BRP) ≠ Escapement Goals BRP are quantitative

Spawners at Maximum Sustainable Yield (MSY)Spawners needed to seed habitat Based on current data not on future expectations

Escapement goals are from policy-technical interaction and ideally are based on fish management philosophyshould include quantitative analysisrisk to persistencefishery stability or maximization of catchuncertainty

OverviewBackground/Available DataApproach & AnalysisInitial Results/ Model PerformanceDevelopment of BRPEscapement Goals for LCR SteelheadSummary/ImplicationsQuestions

Lower Columbia Region (LCR)Four summer and fourteen winter steelhead

populations in Washington

Iteroparous with repeat spawner rate of 5% to 15%

Hatchery releases beginning in 1950’s with Mitchell Act program

Different populations have different levels of hatchery influence and broodstock types

HatcheriesHatchery program

Chambers Cr winters (Puget Sound origin)Skamania summers (Washougal origin)Local broodstocks (Cowlitz, Kalama, Abernathy)

Relative Reproductive Success (RRS) to smolt stageChambers (6%) measured in Forks Creek,Skamania (30-35%)Kalama & Clackamas River, Wild Broodstock (>80% -adult stage Hood &

Kalama)

HarvestMainstem Columbia River - Mixed

Stock Fisheriescommercial fisheries- managed for < 2%

incidental catch Stock composition of steelhead catch in

both commercial and Treaty fisheries (above BON) is unknown

Sport fisheries have been operated under wild steelhead release since 1984

Adult Trapping Mark/Re-sight via Snorkeling

Redd Surveys Juvenile Trapping

Smolt Trapping with concurrent Adult Escapement data

LCR Steelhead ChallengesShort data series and high measurement

error for redd counts (coefficient of variation ~ 30%)

Standard salmon spawner to adult recruit relationships do not account for iteroparity

Ocean survival has varied over 10-fold in the LCR introducing much variation in adult recruits

Different proportions of hatchery spawners with limited measurements of RRS

ApproachStandardized spawners into wild equivalents

using appropriate RRS estimates to discount hatchery spawners to the smolt stage

Standardized SR data into fish density (fish per square kilometer of drainage area)

Developed spawner to smolt relationships to reduce environmental variation caused by 10-fold changes in marine survival and lack of mainstem Columbia River catch estimates by stock

Autocorrelation is not an issue using spawner and smolts

Hierarchical modeling (meta-analysis) using different spawner-smolt-relationships (SRR)

Hierarchical ModelingBorrow strength from other curves -

from those with more dataEstimates shrink towards the mean,

which yields improved precision of individual BRP

Compromise between individual and fully pooled estimates

Reduces overfitting of individual curvesAllows individual curves to be fit in

cases, where there are few data points, outliers, etc.

Common set of steelhead spawner to smolt relationships

Spawner to smolt functions come from a random sample of S/R distributions that can be hierarchically modeled.

AnalysisBarrowman, N.J., R.A. Meyers, R.

Hilborn, D.G. Kehler, and C.A. Field. The variability among populations of coho salmon in maximum reproductive rate and depensation. Ecological Applications 2003:784-793. (used km available)

Smolts and spawners per sq. km of drainage area, with spawners adjusted for RRS data

Bayesian hierarchical analysis using WinBUGS with Lognomal error

Vague priors similar to Barrowman so the results are data driven not prior driven

Checked convergence with Brooks-Gelman-Ruben (BGR) statistics.

HierarchicalBHRHS

Wild Equivalent Spawners per Square Kilometer

Sm

olts per Square K

ilometer

Grays

0

30

60

90

120

150

0 2 4 6

Mill

0

30

60

90

120

150

0 2 4 6

Abernathy

0

30

60

90

120

150

0 2 4 6

Germany

0

30

60

90

120

150

0 2 4 6

Coweeman

0

30

60

90

120

150

0 2 4 6

Kalama

0

30

60

90

120

150

0 5 10 15 20

Cedar

0

30

60

90

120

150

0 2 4 6

Trout

0

30

60

90

120

150

0 2 4 6

Wind

0

30

60

90

120

150

0 2 4 6

NF Toutle

0

30

60

90

120

150

0 2 4 6

EF Lewis

0

30

60

90

120

150

0 2 4 6

ResultsDeviance Information Criteria (DIC) is a

Bayesian analog for Akiake Information Criteria (AIC)

Using DIC for model selection BH and HS models were preferred over Ricker model.

These results are consistent with other analysis for yearling anadromous salmonids, that dome shape models (Ricker) do not fit this life history type well.

Mill

0

30

60

90

120

150

0 2 4 6

Germany

0

30

60

90

120

150

0 1 2 3 4 5

Wind

0

30

60

90

120

150

0 2 4 6

•Yellow Line- drainage area only•Fitting a curve with no S/R data

•Pink Line – Individual estimate

Model Performance

Wild Equivalent Spawners per Sq. KM

Smolts per Sq km

Snow Cr, WA-Puget Sound (40 sq km)

0

20

40

60

80

0 1 2 3 4 5 6

Asotin Cr, WA-Snake (1166 sq km)

0

20

40

60

80

0 1 2 3 4 5 6

NF Scapoose, OR-LCR (61 sq km)

0

20

40

60

80

0.0 0.5 1.0 1.5 2.0

NF Newhalem, OR-Coast (112 sq km)

0

20

40

60

80

100

0 4 8 12 16 20

EF Trask, OR-Coast (74 sq km)

0

20

40

60

80

100

120

140

0 1 2 3 4 5 6

Mill-Siletz, OR-Coast (33 sq km )

0

20

40

60

80

0 1 2 3 4 5 6 7

Mill-Yaquina, OR-Coast (19 sq km)

0

20

40

60

80

0 1 2 3 4 5 6

Cascade, OR-Coast (14 sq km)

0

20

40

60

80

0 1 2 3 4 5

SF Smith, OR-Coast (65 sq km)

0

20

40

60

80

100

120

140

0 3 6 9 12 15

Basin Model w/95%CI Superimposed over PNW Population outside LCR

Biological Reference Points

B = spawners needed to produce 50% of asymptotic smolt estimateS* = inflection point in curve, spawners needed to seed habitatMSP = spawners needed to produce maximum smolt productionK = smolt capacity estimateProductivity = slope of curve at origin; est. of population resiliency.

Estimates of Seeding Levels

0%

20%

40%

60%

80%

100%

0 5 10Wild Equivalent Spawners per Square

Kilometer

Cre

dib

le I

nte

rval

S*

MSP

B

Capacity Estimates

0%

20%

40%

60%

80%

100%

0 50 100 150 200

Smolts per Square Kilometer

Cre

dib

le I

nte

rval

HS

BH

Productivity Estimates

0%

20%

40%

60%

80%

100%

0 100 200 300 400

Smolts per Square Kilometer

Cre

dib

le I

nte

rval

HS

R

BH

•Seeding Levels = 0.4 to 1.7Wild Equiv.Spawners per KM^2

•Smolt Capacity = 43 to 55 smolts per KM^2

• Productivity = 66 to 137 smoltsper KM^2

Historic Escapement GoalsBest professional opinion

US v. Oregon TAC recommended 1000 steelhead spawners for the Wind River.

Application of Boldt Case (Puget Sound & Washington Coast) Potential Parr Production model to LCRLucas and Nawa (1985) recommended 1400 steelhead

spawners for the Wind River

Hierarchical Modeling ApproachUsing BRP - ~500 spawners for the Wind

River (using HS model)

Summary & ImplicationsBRP are quantitative

useful in developing Escapement Goals.Hierarchical Model Approach can provide

estimates of BRP even for populations with little or no SR data.

Individual curves are improved when data is available.

Basin model sensitive to RRS and HOS estimates, and when spawners use a low fraction of drainage area (Mill-LCR, NF Scappoose)

Basin model potentially useful outside LCR except very small tributaries (OR coast)

Next Steps – model improvement by incorporating steelhead distribution and/or GIS attributes

Summary & ImplicationsIn LCR populations – it appears we have been

achieving seeding levels or higher in most years.In LCR - 12/95 (13%) spawner points < S*Reassessment of current Escapement Goals for

LCR steelhead populations is likely warranted.If LCR steelhead recovery requires improvement in

adult abundance: increase habitat capacity because we are

seeding habitat.and increase wild stock productivity by

decreasing pHOS

•Multiple funding sources •NOAA through Mitchell Act, •Bonneville Power Administration• WDFW

•Data•Asotin – Mark Schuck (WDFW)•OR Coast – Eric Suring (ODFW)•Snow Ck – Randy Cooper (WDFW)

•WDFW•KRT - Coweeman and Kalama•WSPE - Mill, Abernathy, Germany, NF Toutle•Region 5 Fish Mgt - Grays, Cedar, EF Lewis, Wind, & Trout •Many techs and bios who collected 95 spawner and smolt points since 1977.