Chris Bare, Jim Latshaw, Ian Tattam, Jim Ruzycki, and Rich Carmichael Estimating Chinook escapement...
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Chris Bare, Jim Latshaw, Ian Tattam, Jim Ruzycki, and Rich Carmichael
Estimating Chinook escapement to the John Day River basin using a mark-recapture approach
Presentation Outline
Monitoring adult spring Chinook
– Redd counts at index sites
– Redd counts at census sites
– Mark-recapture using PIT tag detections
2
3
John Day River Basin
OREGON
4
IndexCensus
Total survey = 268 km29% Index, 71% Census
Redd Surveys
520
0020
0220
0420
0620
0820
1020
1220
140
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
Jo
hn
Da
y E
sc
ap
em
en
t𝑹𝒆𝒅𝒅𝑻𝒐𝒕𝒂𝒍 ∙( 𝑭𝒊𝒔𝒉𝑹𝒆𝒅𝒅 )=𝑺𝒑𝒂𝒘𝒏𝒆𝒓𝒔
6
Concerns with Redd Counts– Index bias– Census assumptions – Detection probability
7
John Day Dam vs. Census Redd Counts
0 100,000 200,000 300,0000
500
1,000
1,500
2,000
2,500
John Day Dam Spring Chinook
Ce
ns
us
Re
dd
Co
un
ts
8
PIT-tagging Chinook in the John Day Basin
92000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
10,000 South ForkNorth ForkMiddle ForkUpper MainstemLower Mainstem
PIT
-ta
gg
ed
Ch
ino
ok
PIT-tagged John Day Juvenile Chinook
10
Columbia River
Pac
ific
Oce
an
BON TDA
MJ1
Detection Site
Survey Reach
11
Estimating Abundance via Mark-Recapture
: estimated number of adult John Day Chinook at PIT tag array
Mark (M ): PIT-tagged adult John Day origin Chinook detected at array
Capture (C ): intact carcasses scanned for PIT tag on spawning grounds
Recapture (): fish in group M recovered on spawning grounds
12
- Closed population: 100% homing from detection arrays to spawning grounds
- Equal pre-spawn mortality among marked and unmarked fish
- Marks are retained during upstream migration
- Equal number of marked males and females
- Mark does not affect probability of detection
- Observers correctly record all marks
Mark-Recapture Assumptions
132009 2010 2011 2012 2013 2014
0
200
400
600
800
1,000
1,200
1,400
1,600MarkCaptureRecapture
Ch
ino
ok
Basinwide Marks, Captures, and Recaptures
665
24 9 1612
14
2009 2010 2011 2012 2013 20140
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000Mark-Recapture
Redd Expansion
Ch
ino
ok
Basinwide Abundance Estimates
152012 2013 2014
0
100
200
300
400
500
600MarkCaptureRecapture
Ch
ino
ok
Middle Fork Marks, Captures, and Recaptures
16
2012 2013 20140
500
1,000
1,500
2,000
2,500Mark-Recapture
Redd Expansion
Ch
ino
ok
Middle Fork Abundance Estimates
17
PIT-falls…
18
Basinwide Redd Expansion vs. Mark-Recapture Estimates
3,5004,0004,5005,0005,5006,0006,5007,0007,5002,000
4,000
6,000
8,000
10,000
12,000
Ma
rk-R
ec
ap
ture
Es
tim
ate R = 0.427
p = 0.399
19
900 1,100 1,300 1,500 1,700 1,900 2,100 2,3002,000
4,000
6,000
8,000
10,000
12,000
Census Redds
Ma
rk-R
ec
ap
ture
Es
tim
ate R = 0.792
p = 0.060
Basinwide Redd Counts vs. Mark-Recapture Estimates
20
Future Directions
• Genetic Stock Identification
• Better understanding of survival during adult life history
21
Acknowledgements
• Oregon Watershed Enhancement Board• Bonneville Power Administration• Confederated Tribes of the Warm Springs
Reservation• Private landowners• Field crew and volunteers
Chris Bare, Jim Latshaw, Ian Tattam, Jim Ruzycki, and Rich Carmichael
Estimating Chinook escapement to the John Day River basin using a mark-recapture approach