presentation to the fish tagging forum of the northwest power and conservation council march 22,...

Presentation to the Fish Tagging Forum of the Northwest Power and Conservation CouncilMarch 22, 2012

PIT Tagging and White Sturgeon Assessments

Topics

A. Overview of Sturgeon Management Areas and Projects

B. Broad Management QuestionsC. Examples of how PIT tags are improving

assessmentsD. Down sides of PIT tags for sturgeon?

Com

l ub ia

iR

v e r

Sr

na

ke

Riv

e

C o

b

l u mia

Ri

evr

Lower M idColumbia

(FCRPS )

Upper M idColumbia(FERC PUDs)

LowerColumbia(O R & W A )

Kootenai(US FW S RT )

UpperS nake River

(FERC I PC)

UpperColumbia

(UCW S RI )

Lower S nake(FCRPS )

oe

n

Ri

K

a i

ot

v e r

Wi

mll

t te

ae

Riv

re

31

32

SturgeonManagementPlanningUnits

SturgeonManagementPlanningUnits

3

Tagged Fish by year and area Sub-Population / Reach

YearBelow Bonneville Bonneville The Dalles John Day McNary

1993 1271994 1,147 3,7391995 5,601 4671996 2,169 4,0891997 3,7991998 2,6411999 3,49120002001 3,7092002 2,7122003 6,3122004 4,7042005 5,2932006 6,9092007 4,5282008 6,3782009 2,853 7,6392010 4,626 4,0392011 3,317 5,175 273

Sum 10,796 24,648 38,484 21,069 740

B. Broad Management Questions

Are populations at risk of extinction?Are there productivity losses and lost harvest

potential due to anthropogenic threats?How have various limiting factors and threats

affected vital rates? How effective are management actions at

reducing threats?What are appropriate sustainable harvest

rates in our current environment?

6

Population Attributes needed to address Management Questions

Spawning & Rearing Conditions

Reproduction

Age-1

Eggs

Juvenile Natural Mortality & Unexplained Loss Rates

Growth Function

Predation Mortality Rates

Adult Fishing Mortality Rates

Carrying Capacity

Sub-adult

C. Examples of how PIT tags are improving assessments

Improved Abundance EstimatesMLE survival estimatesAssessing growth rate relative to traditional

methods Assessing transplant supplementation successAssessing hatchery effectivenessAssessing movements among reservoirsAssessing exploitation rate relative to harvest

number

Improved Abundance Estimates

• Short-lived external tags and marks– Limited time-period for recaptures– Petersen-like mark-recapture estimates– N=M*C/R

• Persistent PIT tag– Long time series mark-recapture estimates– Maximum Likelihood Estimator models– Live Dead encounter histories LDLDLDLDLD– Ever growing data set and improved precision over

time

9

Lower Columbia River White Sturgeon

19871989

19911993

19951997

19992001

20032005

20072009

20110

50

100

150

200

250

300

Thou

sand

s

42” – 60” White Sturgeon

Kootenai Adult Sturgeon Abundance

1989 1992 1995 1998 2001 2004 2007

% m

ark

ed

0

20

40

60

80

Kootenai Recapture Rates

Survival Assessments

• Catch rate based assessment of diminishing abundance through time– Catch curves and cohort analyses

• Persistent PIT tag– Long time series mark-recapture estimates– Maximum Likelihood Estimator models– Live Dead encounter histories LDLDLDLDLD– Ever growing data set and improved precision over

time

Catch Curve

Bonneville Juvenile White Sturgeon MLE Annual Survival Rates

1994-1999 1999-2003 2003-2006 2006-20090.800.820.840.860.880.900.920.940.960.981.00

Growth Assessment

Age

Len

gth

Growth Assessment

Fork Length (cm)

0 20 40 60 80 100 120 140 160 180 200 220 240 260

Ann

ual G

row

th I

ncre

men

t (c

m/y

r)

0

2

4

6

8

10

Growth Assessment

Fork Length (cm)

0 20 40 60 80 100 120 140 160 180 200 220 240 260

Ann

ual G

row

th I

ncre

men

t (c

m/y

r)

0

2

4

6

8

10

Growth Assessment

Examples of how PIT tags are improving assessments

Improved Abundance EstimatesMLE survival estimatesAssessing growth rate relative to traditional

methods Assessing transplant supplementation Assessing hatchery effectivenessAssessing movements among reservoirsAssessing exploitation rate relative to harvest

number

D. Down sides of PIT tags for sturgeon? Strengths | Shortcomings

• Persistent individual mark readily identified by co-managers

• Non-lethal detection • Centralized data

storage• Tiny size

• Extra gear for samplers to carry- Special tool to recognize tag

• Limited remote detections• No data volunteered by

anglers• Relatively expensive. Esp.

w/o NPCC purchase agreements

• Tag placement• Historic issues with vendors

and coding