Indicators of Chinook Abundance, Growth, and Health Scott Hansen Wisconsin Department of Natural...
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![Page 1: Indicators of Chinook Abundance, Growth, and Health Scott Hansen Wisconsin Department of Natural Resources.](https://reader031.fdocuments.net/reader031/viewer/2022013101/56649f255503460f94c3c108/html5/thumbnails/1.jpg)
Indicators of Chinook Abundance, Indicators of Chinook Abundance, Growth, and HealthGrowth, and Health
Scott HansenScott Hansen
Wisconsin Department of Natural ResourcesWisconsin Department of Natural Resources
![Page 2: Indicators of Chinook Abundance, Growth, and Health Scott Hansen Wisconsin Department of Natural Resources.](https://reader031.fdocuments.net/reader031/viewer/2022013101/56649f255503460f94c3c108/html5/thumbnails/2.jpg)
Michigan/Wisconsin Weir Returns
Chinook salmon catch rates (MI charter)
Angler Success (Harvest > 3 Chinook salmon per day MI)
Num
ber
• 1,
000
P
erce
nt o
f A
ngle
rs
Num
ber
per
hr
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0
5
10
15
20
25
30
35
0
10
20
30
40
50
60
70
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Lake-wide Stocking and Harvest(Chinook salmon only)
0
1
2
3
4
5
6
7
8
9
Sto
ckin
g (
mill
ion
s o
f sm
olt
s)
0
2
4
6
8
10
12
Har
vest
(m
illio
ns
of
po
un
ds)Stocked
Harvest
StockingReductions
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Estimated Chinook Salmon Recruitment in Lake Michigan, 1967-2009
0
2
4
6
8
10
12
Mill
ions
of sm
olts
Total StockedNatural
Year Class
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Collection Y
ear
Year Class
2006 2007 2008 2009 2010
2007 57.7
2008 82.9 55.3
2009 65.7 62.3 53.5
2010 67.2 61.5 69.1 54.5
2011 Age-5 Age-4 Age-3 Age-2 Age-1
OTC Project Results
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Growth/Condition Indices
• Salmon growth and condition– Index of forage availability and pred/prey balance– Provides information to aid stocking decisions– Several “Red Flags” indices:
• Creel weight at age 2+
• Weir weight at age 3+
• Weir standard weight of a 30” Chinook
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Weight at age 3(Strawberry Creek weir)
Weight at age 2(June-July MI fishery)
Standard weight(Strawberry Creek weir)
G
ram
s
Gra
ms
G
ram
s
3000
4000
5000
6000
7000
8000
9000
10000
11000
3400
3600
3800
4000
4200
4400
4600
4800
1000
1500
2000
2500
3000
3500
4000
4500
5000
5500
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Lake Trout egg thiamine
concentration
Signs of disease at weirs(percent healthy)
Salmonine composition(percent non-Chinook)
Nm
ol /
gra
m
Per
cent
P
erce
nt
80
85
90
95
100
0
10
20
30
40
50
60
70
80
0
2
4
6
8
10
12
14
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Salmonid Community Composition
Chinook salmon
Lake trout
Coho
Rainbow trout
Brown trout
0%10%20%30%40%50%60%70%80%90%
100%
Year
Per
cent
of
the
harv
est
![Page 10: Indicators of Chinook Abundance, Growth, and Health Scott Hansen Wisconsin Department of Natural Resources.](https://reader031.fdocuments.net/reader031/viewer/2022013101/56649f255503460f94c3c108/html5/thumbnails/10.jpg)
Summary
• Natural reproduction is high (> 50%)
• 2011 alewife recruitment low
• Catch rates recently stabilized (MI waters)– Lower Chinook harvest in WI in 2011
• Improving size at age– 2010 alewife year class assimilated well into population
• Disease incidence very low
• Salmonine composition improved