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Linking freshwater habitat to
salmonid productivity
Watershed Program1
1. NW Fisheries Science Center
2725 Montlake Blvd. East, Seattle, WA 98112-2097
Capacity and Survival

Capacity

Maximum number of fish at a life stage that can be
produced under average annual environmental
conditions





Total surface area
Instream habitat
Food supply
Water quality
Survival

The number of fish that live between life stages




Flows
Sedimenation
Pollutants
Water quality
Number of recruits
Spawner recruit relations and the effect of
altered capacity or survival
Number of spawners
Number of recruits
Spawner recruit relations and the effect of
altered capacity or survival
Change in capacity
Number of spawners
Number of recruits
Spawner recruit relations and the effect of
altered capacity or survival
Change in survival
Number of spawners
Carrying capacity –
life stage distinctions for fall & spring
chinook
Spawning
Fry
Parr
(<45mm)
(45-70mm)
Smolt
Smolt
(freshwater) (estuary/
(>70mm)
nearshore)
(>70mm)
Total habitat
area
Food supply
+/-, +/-
+/-
+/-,+/-
+/-
+/-,+/-
+/-
+/-
+/-
+/-,+/-
Total habitat area
Spawning capacity example - North Fork Stillaguamish
Estimated # of spawning chinook
Total habitat area
North Fork Stillaguamish chinook spawning capacity
80,000
70,000
Total Area (m2)
60,000
Spawn Riffle area (% )
50,000
Spawn Pool area (% )
40,000
Riffle area (% )
Spawn Glide area (% )
Pool area (% )
30,000
Glide area (% )
Redd Size (m2)
20,000
Adults per Redd
10,000
0
-2.0
0.0
2.0
4.0
Range
6.0
8.0
10.0
Total habitat area
North Fork Stillaguamish chinook spawning capacity
Frequency of estimate
450
400
Estimate w data source #1
350
Estimate w data source #2
300
250
200
150
100
50
0
0
25,000
50,000
75,000 100,000 125,000 165,000 190,000
Chinook redd capacity
How do we compare capacities among life
stages and habitat types ?

habitat area × average fish density
 n  n


N       A ij   d i  

 i 1   j1 

 

Aij = is the sum of areas of all habitat
units (j =1 through n) of type I.

di = density of fish in habitat type i.
Habitat type preference juvenile salmonid use

1.4
1.2
1
0.8
0.6
0.4
0.2
chinook(0)
0
es
tua
ry
po
nd
s
nn
el
tem
steelhead (+1,+2)
sid
ec
ha
ma
i ns
rie
s
coho (0,+1)
trib
uta
Juvenile salmonid/m2
1.6
Classification of
habitat types
allows
assessment of
fish use patterns
and expansion to
larger aggregate
units (e.g.,
watersheds)
How do we compare capacities among
life stages and habitat types ?

Estimate (N) for each life stage in a given habitat
Multiply
by density independent survival to smolt
stage
habitat
Smolt
area × average fish density × survival to smolt
production potential can then be compared in
terms of number of smolts ultimately produced.
Change in historic v. current coho
smolt potential production
3,000,000
Coho smolts
2,500,000
Trib Loss
Mainstem Loss
Slough Loss
Pond Loss
Current
2,000,000
1,500,000
1,000,000
500,000
0
Skagit
Stillaguamish
Range of current estimated v. measured
coho smolt potential production
1,400,000
1,200,000
1,000,000
800,000
600,000
400,000
Maximum
Mean
200,000
Minimum
0
Stillaguamish Stillaguamish
(Pess
(Nelson
estimate)
measured
CWT)
Skagit
(Beechie
estimate)
Skagit (Seiler
screwtrap)
Habitat preference – a change in
freshwater rearing quality
There are 5.4 times as
many juvenile chinook
salmon in natural wood
banks as hydromodified
banks
Beamer et. al., 1998
Beamer et. al., 1998
Chinook (0+)
Summer rainbow (0+)
Summer coho parr
wrootwads
w-single
logs
w- debris
piles
wbankroots
wood
rubble
riprap
plants
cobble
Winter rainbow (0+)
boulder
20
18
16
14
12
10
8
6
4
2
0
no cover
Electivity index
Expected change in juvenile salmonid abundance normalized
to abundance in riprap (always = 1.0)
From Beamer,
unpublished data
Chinook salmon redds per km
Habitat preference
Chinook spawning
120
Forced pool-riffle
Plane-bed
Pool-riffle
100
80
60
40
20
0
0
10
20
30
40
Pool spacing (Bankfull channel widths per pool)
Carrying capacity –
Food supply and habitat capacity

Slaney and Northcote (1974) -Rainbow trout (0+)


Giannico (2000) – Coho (0+)



High prey density, less change in territory size
Food supply high – found in pools with little wood
cover
Food supply low – found in pools with abundant wood
A small change in food supply can
effect capacity by altering territory size
and density of salmonids
Survival – life stage distinctions for fall &
spring chinook
Egg to fry
Fry to parr
Parr to smolt
Freshwater to
estuarine/
nearshore
Temperature
+/-
+/-
+/-
+/-
Sedimentation
+/-
+/-
+/-
+/-
+/-
+/-
+/-
Food supply
Flows
+/-
+/-
+/-
+/-
Water quality
+/- (?)
+/- (?)
+/- (?)
+/-
Estimated egg to migrant
fry survival
Peak flows and egg to migrant fry survival
estimates - Skagit Chinook (1989-1996)
(Seiler & others 1998).
18%
16%
14%
12%
10%
8%
6%
4%
2%
0%
y = -4E-05x + 0.1745
R2 = 0.86
0
1000
2000
3000
4000
Annual maximum discharge (cms)
5000
Estimated egg to migrant
fry survival
Peak flow recurrence interval and egg to
migrant fry survival estimates - Skagit Chinook
(1989-1996)
18%
16%
14%
12%
10%
8%
6%
4%
2%
0%
egg to fry survival = 0.1284e-0.0446(flood recurrence interval)
R2 = 0.97
0
20
40
60
Flood reccurence interval (years)
80
Chinook recruits/spawner v.
flood recurrence interval
Chinook recruits per spawner
7
Cascade summer run
Lower Skagit fall run
Upper Skagit summer run
Upper Sauk spring-run
Lower Sauk summer-run
Suiattle spring-run
Stillaguamish summer-run
6
5
4
3
2
1
0
0
50
100
Flood recurrence interval (FRI) (years)
150
A change in peak flows in the
North Fork Stillaguamish
1200
Annual maximum
discharge (cms)
1000
800
600
400
y = 180.82x - 331389
200
R2 = 0.29
p < 0.001
0
1920
1940
1960
Year
1980
2000
A change in peak flows in the
North Fork Stillaguamish
Annual maximum
discharge (cms)
1200
1972 to 1995
1950 to 1971
1928 to 1949
1000
800
600
400
200
0
1
10
Recurrence interval (year)
100
Sensitivity of regression to changes in peak
flows in the North Fork Stillaguamish
14%
10%
Survival for 1972 to 1995 flow conditions
Estimated egg to fry
survival
12%
Survival for 1928 to 1949 flow conditions
Survival for 1950 to 1971 flow conditions
8%
6%
4%
2%
0%
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
Recurrence interval (year)
Estimated egg to fry
survival (%)
Survival –
Scour? Entombment? Oxygenation?
Downstream displacement?
1
0.8
0.6
0.4
0.2
0
0
10
20
30
40
50
Scour depth (cm)
(could also be fines %, peak flows (cms))
Survival – peak flow caveats

Cannot break down survival by mechanism

Keep mechanisms lumped

Egg to fry




Fry to smolt



Entombment
Scour
Oxygenation
Predation
Downstream displacement
Different relationship in Columbia River Basin

Rain-on-snow v. snow-dominated
Survival – Food supply

Slaney & Ward (1993) – Steelhead (1+,2+)

Increase in phosphorus & nitrogen

Increase in smolt to adult survival
(1+) - +62%
 Smolts – +30% to 130%


Being clear about assumptions and model choice

Do a sensitivity analysis where possible

Run multiple scenarios with different datasets

Many relationships are not universal


Puget Sound v. Columbia Basin flow example
Keep it simple

Do not assume cause and effect mechanism unless it is clear

Egg to outmigrating fry example

Keep numbers local where possible

Check model numbers against real fish numbers