spatial and temporal distribution of adult summer steelhead in asotin creek, washington ethan...

Spatial and Temporal Distribution of Adult Summer Steelhead in

Asotin Creek, Washington

Ethan Crawford and Michael HerrWashington Department of Fish & Wildlife

© Joesp

h

Tom

elle

ri

Background• BPA funded RM&E project focused on

calculating VSP metrics outlined by McElhany et al 2000.

• Operating a juvenile trap since 2004, adult trap since 2005.

• Project is a product of all the efforts that preceded it; Asotin Creek Model Watershed, habitat projects (million$), etc.

NMFS funded Intensively Monitored Watershed began in 2008 (EcoLogical Research, Inc.)

Study Area

The Need• We needed a way to provide

estimates of spatial and temporal distribution in the tributaries.

-Index Redd surveys have been historically completed with LSRCP funding by Snake River Lab staff.

GOAL: To use PIT tag interrogation data to describe spatial and temporal distribution by tributary.

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

2010

2012

2014

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80Historic Redd Data

Main

North

South

Charley

Spawn Year

Pro

port

ion

of

Sp

aw

ners

Data courtesy of Todd Miller and Joe Bumgarner, WDFW

Methods• Since 2010, all untagged wild adult

steelhead captured have been PIT tagged.

• Data are then entered into an MS Access database.

• Passive observations and interrogation data then merged and dumped into the project database.

Charley Creek (CCA)

Asotin Forks (AFC)

Results• We found that estimates of

escapement to the tributary are similar and at the very least no worse than redd surveys.T-test: In all instances we failed to reject H0: Redds=Fpit

60%22%

10%

8%Fpit Main

stem

NF

SF

CC

54%

24%

11%

10% Redds

Weir Timing

0

5

10

15

20

25

30

35

40

45

502010

Mainstem NF

SF CC

Undetermined

Capture Date

Nu

mb

er

of

Fis

h

Tributary Run Timing

25 48 71 94 1171401630

0.2

0.4

0.6

0.8

1

1.2

2010

25 45 65 85 105125145165

2011

25 45 65 85 105125145165

2012

25 41 57 73 89 1051211371530

0.20.40.60.8

11.2

2013

25 39 53 67 81 95 109123137151165

2014

Pro

port

ion

of

Ad

ult

s

Julian Date

Charley South Fork North Fork

Mai

nste

m NF SF CC

Mai

nste

m NF SF CC

Mai

nste

m NF SF CC

Mai

nste

m NF SF CC

Mai

nste

m NF SF CC

2010 2011 2012 2013 2014

500

520

540

560

580

600

620

640

660

680

700

Mean Fork LengthFo

rk L

engt

h(m

m)

Mai

nste

m NF SF CC

Mai

nste

m NF SF CC

Mai

nste

m NF SF CC

Mai

nste

m NF SF CC

Mai

nste

m NF SF CC

2010 2011 2012 2013 2014

500

520

540

560

580

600

620

640

660

680

700

Mean Fork LengthFo

rk L

engt

h (m

m)

2010 2011 2012 2013 2014 Average0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1Charley NF SF Mainstem Undetermined

Spawn Year

Pro

port

ion

Male

Sex Ratio

Main NF

SF

CC

Main NF

SF

CC

Main NF

SF

CC

Main NF

SF

CC

Main NF

SF

CC

2010 2011 2012 2013 2014

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1.1 1.2 2.1 2.2 3.1 3.2 4.1 Unreadble Repeats

Perc

en

tag

e o

f A

du

lts

Age Composition

Conclusions• Using PIT tag observations to

document spatial and temporal distribution is effective and affordable for even the smallest projects.

• Though utility of PIT tag observations can be limited for the same reasons that redd surveys are.

• PIT tag data allows us a more detailed view of the spawning population and its attributes.

Questions?