e ffect of s ize - at t agging on the a pparent s urvival of c hinook s almon in e ntiat r iver, w...
TRANSCRIPT
EFFECT OF SIZE-AT TAGGING ON THE APPARENT SURVIVAL OF CHINOOK
SALMON IN ENTIAT RIVER, WASHINGTON
PIT Tag Workshop Skamania Lodge, Washington – January 27th - 29th, 2015
Presenter:
Michael B. Ward
Collaborators:
Shubha Pandit, Tom Desgroseillier, Keith van den Broek, Michael B. Ward, Chris Jordan, Pamela Nelle , Carl Saunders, Kevin See
Objectives
• To determine if there is an effect of fish size at tagging on the apparent overwinter survival rate for Chinook salmon in the Entiat River subbasin.
• To determine if changing the minimum size at tagging would be problematic for survival time-series
Background
• Permits since 2011: may tag fish 50-59mm fork length using 9mm PIT tags, ≥60mm using 12mm PIT tags
• Proposed restrictions: may not tag fish 50-59mm; fish from 60-69 may only be tagged with 9mm PIT tags, ≥70mm using 12mm tags
• Proposed restrictions could confound results from on-going studies if detectability or survival rates vary by size class
• Proposed restrictions may not be justified through improvements in survival
• Change is occurring towards the end of a critical evaluation period (the 2008-2018 Biological Opinion)
Literature: Size at Tagging on Survival
• Coho: (Many papers, esp. Brakensiek and Hankin 2007; Ebersole et al. 2006; Pess et al. 2011; Quinn and Petersen 1996; etc.).
• Steelhead: (Tatara 2009; Connolly and Petersen 2003; Zabel et al. 2005).• Chinook: (Zabel and Achord 2004; Zabel et al. 2005; Knudsen et al 2009)• Zabel and Achord 2004: relative fish length vs. absolute fish length
• most studies report relative fish length within populations, is significantly related to survival
• absolute fish length is not significantly related to survival• but proposed permit restrictions are in absolute fish length
• Zabel et al. 2005: relationship between survival and relative fish length varies across populations and years
• In juvenile brown trout and Atlantic salmon impact of PIT tags (11 to 12 mm) on growth and mortality was negligible (Ombredane et al, 1998; Gries and Letcher, 2002),
• A few studies (e.g., Brown et al. 2013) showed only tag burden (ratio of transmitter weight to fish weight) was a concern for mortality.
Methodology• Entiat Intensively Monitored
Watershed
• 7,732 Chinook salmon tagged
• Summer 2010 – Winter 2013
Mad River
VS1
VS2
VS3
Methodology
• Repeated these analyses with equal sample sizes
• The entire data set with fork length as a covariate
• Survival estimates calculated using the Barker model for:
• Varying size classes
• 50-120mm, 60-120mm, 70-120mm, 80-120mm
• Four discrete size classes i.e., 50-59, 60-69, 70-79, 80-120mm
Methodology
• Repeated these analyses with equal sample sizes
• The entire data set with fork length as a covariate
• Survival estimates calculated using the Barker model for:
• Varying size classes
• 50-120mm, 60-120mm, 70-120mm, 80-120mm
• Four discrete size classes i.e., 50-59, 60-69, 70-79, 80-120mm
Absolute Fish Length
Relative Fish Length
Methodology- Model Selection and Goodness of Fit• Barker model
• Ten candidate models: fully time varying or time constant
• Selection using evidence (weight) ratio derived from the Quasi-likelihood Akaike Information Criterion (QAIC) adjusted for over-dispersion
• Used bootstrap simulations to quantify goodness of fit
Results: Varying Size Classes
Valley segments of Entiat River and Mad River
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
No. tagged = 7,732
50 - 120mm
Surv
ival
pro
babi
lity
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
VS1 VS2 VS3 Mad
Results: Varying Size Classes
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
60 - 120mm
No. tagged = 6,780
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
70 - 120mm
No. tagged = 5,471
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
80 - 120mmNo. tagged = 3,348
Valley segments of Entiat River and Mad River
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
No. tagged = 7,732
50 - 120mm
Surv
ival
pro
babi
lity
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
VS1 VS2 VS3 MadVS1 VS2 VS3 MadVS1 VS2 VS3 MadVS1 VS2 VS3 Mad
Results: Varying Size Classes
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
60 - 120mm
No. tagged = 6,780
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
70 - 120mm
No. tagged = 5,471
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
80 - 120mmNo. tagged = 3,348
Valley segments of Entiat River and Mad River
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
No. tagged = 7,732
50 - 120mm
Surv
ival
pro
babi
lity
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
VS1 VS2 VS3 Mad0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
tedate
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
VS1 VS2 VS3 Mad
No. tagged = 3,348 No. tagged = 3,348
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
VS1 VS2 VS3 Mad
No. tagged = 3,348No. Marked/Released =
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
imat
e
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
imat
e
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
VS1 VS2 VS3 Mad
No. tagged = 3,348
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
Results: Length as a Covariate
Fork Length (mm)
Surv
ival
pro
babi
lity
0.0
0.2
0.4
0.6
0.8
1.0
60 80 100 120 60 80 100 120 60 80 100 120
Aug 2010-March 2011 Aug 2011-March 2012 Aug 2012-March 2013
Results: Varying Size Classes
Unequal Sample Size
0.0
0.1
0.2
0.3
0.4
0.5
0.6
60 - 120
70 - 120
80 - 120
50 - 120
F3,34= 0.023, p = 0.97F3,34 = 0.18, p = 0.83
Size class (mm)
Surv
ival
pro
babi
lity
Equal Sample Size=3,348
60 - 120
70 - 120
80 - 120
50 - 120
Results: Discrete Size Classes
Size class (mm)
F3,30=2.48, p=0.07
Surv
ival
pro
babi
lity
0.0
0.2
0.4
0.6
0.8
1.0
50 - 59 60 - 69 70 - 79 80 -120
F3,24=0.42, p=0.73
Unequal Sample Size Equal Sample Size=3,348
50 - 59 60 - 69 70 - 79 80 -120
Results: Year Effect August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013Equal Sample SizeUnequal Sample Size
Size class (mm)
Surv
ival
pro
babi
lity
Size class × Year: F6, 22=1.43, p=0.25 Size class × Year: F6, 16=1.91, p=0.14
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
50 - 59 60 - 69 70 - 79 80 -120 50 - 59 60 - 69 70 - 79 80 -120
Discrete Size Classes
-0.1
0.0
0.1
0.2
0.3
0.4
0.5Size class × Year: F6, 36=0.19, p=0.97Size class × Year: F6, 36= 0.09, p=0.99
60 - 120
70 - 120
80 - 120
50 - 120
60 - 120
70 - 120
80 - 120
50 - 120
Varying Size Classes
Results: Secesh R.
Preliminary results from ISEMP work in the Secesh, courtesy QCI.
Summary: Secesh River (preliminary results)
• Time of tagging and or timing of emigration plays a larger role in juvenile mortality than size at tagging
• Failure to tag fish <60mm would result in a failure to tag about half of the population prior to emigration
• The Secesh is fairly typical of Idaho streams – high gradient and cold – greater than 50% of juveniles leave these systems before they’d be taggable under the proposed size restrictions
• Failing to tag fish <60mm would result in non-representative estimates of growth and survival
Summary
• There is a positive relationship between overwinter survival and size-at-tagging in models using size as a covariate. The effect varies by year.
• There is no significant difference in apparent survival estimated for four discrete size groups (50-59, 60-69, 70-79, 80-120 mm), and no significant year effect.
• There is no significant difference in survival for four size groups with varying minimum size limits (50-120, 60-120, 70-120,80-120 mm), and no significant year effect.
• Model estimates of survival did not converge for sample groups with approx. <200 individuals; however, that effect was only seen when looking at finer spatial and temporal groupings, and not at the population level.
Summary
• There is a positive relationship between overwinter survival and size-at-tagging in models using size as a covariate. The effect varies by year.
• There is no significant difference in apparent survival estimated for four discrete size groups (50-59, 60-69, 70-79, 80-120 mm), and no significant year effect.
• There is no significant difference in survival for four size groups with varying minimum size limits (50-120, 60-120, 70-120,80-120 mm), and no significant year effect.
• Model estimates of survival did not converge for sample groups with approx. <200 individuals; however, that effect was only seen when looking at finer spatial and temporal groupings, and not at the population level.
Absolute Fish Length
Absolute Fish Length
Relative Fish Length
Management Conclusions• We see no size-at-tagging effect on survival in Chinook that would
justify a change in NOAA tagging protocols.
• Simulated restrictions in sample size as proposed by NOAA did not affect subbasin- or valley segment-scale survival estimates.
• Simulated restriction in sample size as proposed by NOAA did affect survival estimates at finer spatial/temporal scales.
• We infer that:• Proposed NOAA tagging protocols could impact estimates of other
key parameters such as movement or growth
• Trend information could be confounded by such proposed changes
• Proposed NOAA tagging protocols may have impacts on steelhead parameter estimation (prelim. results, Entiat and John Day).
Fork length class VS1 VS2 VS3 VSMad Subtotal %50-59 mm 321 277 337 7 942 12.2060-69 mm 549 191 570 49 1359 17.6070-79mm 1082 296 551 144 2073 26.85Greater than 80 mm 1637 620 925 166 3348 43.36Subtotal 3589 1384 2383 366 7722% 46.48 17.92 30.86 4.74 100
Size Distribution of Marked Fish
Methodology – Barker Model• The Barker model has been found to be robust in our systems
(Conner et al., 2015)
• The model incorporates resight data which provides a less biased estimate of survival compared with other models
• Encounter history matrix was built using four years data (summer and winter from 2010 to 2013)
• Individuals were marked and released (1), resighted or observed (2), not captured (0), or removed (-1)
Research Questions
1. Does the survival probability increases as fish length at tagging increases?
Surv
ival
Pro
babi
lity
Fork Length at tagging
2. Does the estimated survival probability differ if certain fish length group is excluded? >=60, >70, >80 etc
60 80 100 120
Num
ber o
f Fis
h
Fork Length (mm)
3. What is the survival probability for the discrete classes of fork length at tagging?
Research Questions
4. Since the number of samples sizes are varied among the classes, we further asked the questions of whether the survival probability would differ:
With equal samples sizes among the classes.
With unequal sample size.
Background
• 9mm PIT tags probabilities at In-stream Detection Systems
• The read ranges are typically <50% relative to a 12mm tag
• Therefore we will need to tag more fish to obtain reliable estimates
• ISEMP often tags fish 50-59mm; with rare exceptions, use 12mm tags for fish in the 60-70 range
Size Distribution of Tagged Fish
Fork Length (mm)
No.
of F
ish
Results: Discrete Size Classes
Valley segments of Entiat River and Mad River
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
No. tagged =7,732
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
imat
e
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
No. tagged =942
50 - 120mm
VS1 VS2 VS3 Mad
Surv
ival
pro
babi
lity
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
Results: Discrete Size Classes
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
No. tagged =3,348
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
No. tagged =942
80 – 120mm
VS1 VS2 VS3 Mad
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
No. tagged =2,073
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
No. tagged =942
70 - 79mm
VS1 VS2 VS3 Mad
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
No. tagged =1,359
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
No. tagged =942
60 - 69mm
VS1 VS2 VS3 Mad
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
No. tagged =942
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
No. tagged =942
50 - 59mm
VS1 VS2 VS3 Mad
Valley segments of Entiat River and Mad River
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
No. tagged =7,732
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
imat
e
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013
No. tagged =942
50 - 120mm
VS1 VS2 VS3 Mad
Surv
ival
pro
babi
lity
0.00
0.25
0.50
0.75
1.00
1a 2a 3a 4aSN
Est
ima
te
date
August 2010 - March 2011
August 2011 - March 2012
August 2012 - March 2013